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| mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 1 of 52 data sheet rev 009 june 29, 2015 features and benefits small size, low cost easy to integrate factory calibrated in wide temperature range: -40+125?c for sensor temperature and -70+380?c for object temperature. high accuracy of 0.5c in a wide temperature range (0+50c for both ta and to) high (medical) accuracy calibration measurement resolution of 0.02c single and dual zone versions smbus compatible digital interface customizable pwm output for continuous reading available in 3v and 5v versions simple adaptation for 816v applications sleep mode for reduced power consumption different package options for applications and measurements versatility automotive grade applications examples high precision non-contact temperature measurements thermal comfort sensor for mobile air conditioning control system temperature sensing element for residential, commercial and industrial building air conditioning windshield defogging automotive blind angle detection industrial temperature control of moving parts temperature control in printers and copiers home appliances with temperature control healthcare livestock monitoring movement detection multiple zone temperature control C up to 127 sensors can be read via common 2 wires thermal relay / alert body temperature measurement ordering information part no. mlx90614 temperature code e (-40 c...85 c) k (-40 c125 c) package code sf (to-39) - option c ode - x x x (1) (2) (3) standard part -000 packing form -tu (1) supply voltage/ accuracy a - 5v b - 3v c - reserved d - 3v medical accuracy (2) number of thermopiles: a C single zone b C dual zone c C gradient compensated* (3) package options: a C standard package b C reserved c C 35 fov d/e C reserved f C 10 fov g C reserved h C 12 fov (refractive lens) i C 5 fov example: mlx90614esf-baa-000-tu * : see page 2 1 functional diagram figure 1: typical application schematics 2 general description the mlx90614 is an infra red thermometer for non contact temperature measurements. both the ir sens itive thermopile detector chip and the signal conditionin g assp are integrated in the same to-39 can. thanks to its low noise amplifier, 17-bit adc and powerful dsp unit, a high accuracy and resolution o f the thermometer is achieved. the thermometer comes factory calibrated with a dig ital pwm and smbus (system management bus) output. as a standard, the 10-bit pwm is configured to continuously transmit the measured temperature in r ange of -20120?c, with an output resolution of 0.14?c. the factory default por setting is smbus. j1 con1 scl sda gnd vdd c1 value and type may differ in different applications for optimum emc u1 mlx90614 1 p w m sda c1 mlx90614 connection to smbus 4 vss scl vz m lx90614axx: vdd=4.5...5.5v 3 2 vdd 0.1uf
mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 2 of 52 data sheet rev 009 june 29, 2015 general description (continued) the mlx90614 is built from 2 chips developed and ma nufactured by melexis: the infra red thermopile detector mlx81101 the signal conditioning assp mlx90302, specially de signed to process the output of ir sensor. the device is available in an industry standard to- 39 package. thanks to the low noise amplifier, high resolution 17-bit adc and powerful dsp unit of mlx90302 high accuracy and resolution of the thermometer is achie ved. the calculated object and ambient temperatures are available in ram of mlx90302 with resolution of 0.0 1?c. they are accessible by 2 wire serial smbus compatible protocol (0.02c resolution) or via 10-b it pwm (pulse width modulated) output of the device . the mlx90614 is factory calibrated in wide temperat ure ranges: -40125?c for the ambient temperature and -70380?c for the object temperatur e. the measured value is the average temperature of al l objects in the field of view of the sensor. the mlx90614 offers a standard accuracy of 0.5?c aroun d room temperatures. a special version for medical applications exists offering an accuracy of 0.2?c in a limited temperature range around the human bod y temperature. it is very important for the application designer t o understand that these accuracies are only guarant eed and achievable when the sensor is in thermal equili brium and under isothermal conditions (there are no temperature differences across the sensor package). the accuracy of the thermometer can be influenced by temperature differences in the package induced by c auses like (among others): hot electronics behind t he sensor, heaters/coolers behind or beside the sensor or by a hot/cold object very close to the sensor t hat not only heats the sensing element in the thermometer b ut also the thermometer package. this effect is especially relevant for thermometers with a small fov like the xxc and xxf as the energ y received by the sensor from the object is reduced. therefore, melexis has introduced the xcx version o f the mlx90614. in these mlx90614xcx, the thermal gradien ts are measured internally and the measured temperature is compensated for them. in this way, the xcx version of the mlx90614 is much less sensit ive to thermal gradients, but the effect is not totally el iminated. it is therefore important to avoid the ca uses of thermal gradients as much as possible or to shield the sens or from them. as a standard, the mlx90614 is calibrated for an ob ject emissivity of 1. it can be easily customized b y the customer for any other emissivity in the range 0.11.0 without the need of recalibration with a bl ack body. the 10-bit pwm is as a standard configured to trans mit continuously the measured object temperature for an object temperature range of -20120?c with a n output resolution of 0.14?c. the pwm can be easi ly customized for virtually any range desired by the c ustomer by changing the content of 2 eeprom cells. this has no effect on the factory calibration of the dev ice. the pwm pin can also be configured to act as a ther mal relay (input is to), thus allowing for an easy and cost effective implementation in thermostats or temperature (freezing / boiling) alert application s. the temperature threshold is user programmable. in a sm bus system this feature can act as a processor inte rrupt that can trigger reading all slaves on the bus and to determine the precise condition. the thermometer is available in 2 supply voltage op tions: 5v compatible or 3v (battery) compatible. the 5v can be easily adopted to operate from a high er supply voltage (816v, for example) by use of fe w external components (refer to applications informa tion section for details). an optical filter (long-wave pass) that cuts off th e visible and near infra-red radiant flux is integr ated in the package to provide ambient and sunlight immunit y. the wavelength pass band of this optical filter is from 5.5 till 14m (except for xch and xci type of devic es which incorporate uncoated silicon lens). mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 3 of 52 data sheet rev 009 june 29, 2015 3 table of contents 1 functional diagram .............................. ................................................... ................................................... ................................................. 1 2 general description ............................. ................................................... ................................................... ................................................. 1 3 table of contents ............................... ................................................... ................................................... .................................................. 3 4 glossary of terms ............................... ................................................... ................................................... ................................................. 4 5 maximum ratings ................................. ................................................... ................................................... ................................................. 4 6 pin definitions and descriptions ................ ................................................... ................................................... ............................................. 5 7 electrical specifications ....................... ................................................... ................................................... ................................................. 6 7.1 mlx90614axx ................................... ................................................... ................................................... ............................................ 6 7.2 mlx90614bxx, mlx90614dxx ...................... ................................................... ................................................... ................................ 8 8 detailed description ............................ ................................................... ................................................... ................................................ 10 8.1 block diagram ................................. ................................................... ................................................... ............................................ 10 8.2 signal processing principle ................... ................................................... ................................................... ....................................... 10 8.3 block description ............................. ................................................... ................................................... ............................................ 11 8.3.1 amplifier ................................... ................................................... ................................................... ............................................ 11 8.3.2 supply regulator and por .................... ................................................... ................................................... ............................... 11 8.3.3 eeprom ...................................... ................................................... ................................................... ....................................... 11 8.3.4 ram.......................................... ................................................... ................................................... ........................................... 14 8.4 smbus compatible 2-wire protocol .............. ................................................... ................................................... ................................ 14 8.4.1 functional description ...................... ................................................... ................................................... .................................... 14 8.4.2 differences with the standard smbus specifica tion (reference [1]) .............................. ................................................... ............ 15 8.4.3 detailed description......................... ................................................... ................................................... ..................................... 15 8.4.4 bit transfer ................................ ................................................... ................................................... ........................................... 16 8.4.5 commands .................................... ................................................... ................................................... ...................................... 17 8.4.6 smbus communication examples ................ ................................................... ................................................... ........................ 17 8.4.7 timing specification......................... ................................................... ................................................... ..................................... 18 8.4.8 sleep mode .................................. ................................................... ................................................... ........................................ 19 8.4.9 mlx90614 smbus specific remarks ............. ................................................... ................................................... ........................ 20 8.5 pwm ........................................... ................................................... ................................................... ................................................ 21 8.5.1 single pwm format ........................... ................................................... ................................................... ................................... 22 8.5.2 extended pwm format ......................... ................................................... ................................................... ................................ 23 8.5.3 customizing the temperature range for pwm out put ............................................... ................................................... ................ 24 8.6 switching between pwm / thermal relay and smbus communication .................................... ................................................... ....... 26 8.6.1 pwm is enabled .............................. ................................................... ................................................... ..................................... 26 8.6.2 request condition ........................... ................................................... ................................................... ..................................... 26 8.6.3 pwm is disabled ............................. ................................................... ................................................... ..................................... 26 8.7 computation of ambient and object temperatures ................................................... ................................................... ........................ 27 8.7.1 ambient temperature ta ...................... ................................................... ................................................... ................................ 27 8.7.2 object temperature to ....................... ................................................... ................................................... .................................. 27 8.7.3 calculation flow ............................ ................................................... ................................................... ........................................ 28 8.8 thermal relay ................................. ................................................... ................................................... ............................................. 30 9 unique features ................................. ................................................... ................................................... ................................................ 31 10 performance graphs ............................. ................................................... ................................................... ........................................... 32 10.1 temperature accuracy of the mlx90614 ......... ................................................... ................................................... .......................... 32 10.1.1 standard accuracy .......................... ................................................... ................................................... ................................... 32 10.1.2 medical accuracy ........................... ................................................... ................................................... .................................... 33 10.1.3 temperature reading dependence on v dd .................................................. ................................................... ........................... 33 10.2 field of view (fov) .......................... ................................................... ................................................... ........................................ 35 11 applications information ....................... ................................................... ................................................... ............................................. 39 11.1 use of the mlx90614 thermometer in smbus confi guration .......................................... ................................................... ............... 39 11.2 use of multiple mlx90614s in smbus configurati on ................................................ ................................................... ..................... 39 11.3 pwm output operation ......................... ................................................... ................................................... ...................................... 40 11.4 thermal alert / thermostat.................... ................................................... ................................................... ...................................... 40 11.5 high voltage source operation ................ ................................................... ................................................... ................................... 41 12 application comments ........................... ................................................... ................................................... ........................................... 42 13 standard information regarding manufacturability of melexis products with different soldering proce sses .............................................. . 44 14 esd precautions ................................ ................................................... ................................................... .............................................. 44 15 faq ............................................ ................................................... ................................................... ................................................... ... 45 16 package information ............................ ................................................... ................................................... ............................................. 47 16.1 mlx90614xxa .................................. ................................................... ................................................... ......................................... 47 16.2 mlx90614xcc .................................. ................................................... ................................................... ........................................ 47 16.3 mlx90614xcf .................................. ................................................... ................................................... ........................................ 48 16.4 mlx90614xch .................................. ................................................... ................................................... ........................................ 48 16.5 mlx90614xci .................................. ................................................... ................................................... ......................................... 49 16.6 part marking ................................. ................................................... ................................................... ............................................. 49 16.7 operating and storage humidity range ......... ................................................... ................................................... .............................. 49 17 table of figures ............................... ................................................... ................................................... .................................................. 50 18 references ..................................... ................................................... ................................................... .................................................. 51 19 disclaimer ..................................... ................................................... ................................................... ................................................... . 51 mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 4 of 52 data sheet rev 009 june 29, 2015 4 glossary of terms ptat p roportional t o a bsolute t emperature sensor (package temperature) por p ower o n r eset hfo h igh f requency o scillator (rc type) dsp d igital s ignal p rocessing fir f inite i mpulse r esponse. digital filter iir i nfinite i mpulse r esponse. digital filter ir i nfra- r ed pwm p ulse w ith m odulation dc d uty c ycle (of the pwm) ; d irect c urrent (for settled conditions specifications) fov f ield o f v iew sda,scl s erial da ta, s erial cl ock C smbus compatible communication pins ta a mbient t emperature measured from the chip C (the package te mperature) to o bject t emperature, seen from ir sensor esd e lectro- s tatic d ischarge emc e lectro- m agnetic c ompatibility assp a pplication s pecific s tandard p roduct tbd t o b e d efined note: sometimes the mlx90614xxx is referred as the module. 5 maximum ratings parameter mlx90614esf-axx mlx90614esf-bxx mlx90614esf-dxx mlx90614ksf-axx supply voltage, v dd (over voltage) 7v 5v 7v supply voltage, v dd (operating) 5.5 v 3.6v 5.5v reverse voltage 0.4 v operating temperature range, t a - 40 + 8 5 c -40+125c storage temperature range, t s - 40 +1 2 5 c -40+125c esd sensitivity (aec q100 002) 2kv dc current into scl / vz (vz mode) 2 ma dc sink current, sda / pwm pin 25 ma dc source current, sda / pwm pin 25 ma dc clamp current, sda / pwm pin 25 ma dc clamp current, scl pin 25 ma table 1: absolute maximum ratings for mlx90614 exceeding the absolute maximum ratings may cause pe rmanent damage. exposure to absolute-maximum-rated conditions for e xtended periods may affect device reliability. mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 5 of 52 data sheet rev 009 june 29, 2015 6 pin definitions and descriptions figure 2: pin description pin name function scl / vz serial clock input for 2 wire communications protoc ol. 5.7v zener is available at this pin for connection of external bipolar transistor t o mlx90614axx to supply the device from external 8 16v source. sda / pwm digital input / output. in normal mode the measured object temperature is available at this pin pulse width modulated. in smbus compatible mode the pin is automatically c onfigured as open drain nmos. vdd external supply voltage. vss ground. the metal can is also connected to this pin . table 2: pin description mlx90614 note: for +12v (+8+16v) powered operation refer to the a pplication information section. for emc and isothermal conditions reasons it is highly recommen ded not to use any electrical connection to the met al can except by the vss pin. with the scl / vz and pwm / sda pins operated in 2- wire interface mode, the input schmidt trigger func tion is automatically enabled. bottom view 2 - sda / pwm 4 - vss 3 - vdd 1 - scl / vz mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 6 of 52 data sheet rev 009 june 29, 2015 7 electrical specifications 7.1 mlx90614axx all parameters are valid for t a = 25 ?c, v dd =5v (unless otherwise specified) parameter symbol test conditions min typ max units supplies external supply v dd 4.5 5 5.5 v supply current i dd no load 1.3 2 ma supply current (programming) i ddpr no load, erase/write eeprom operations 1.5 2.5 ma zener voltage vz iz = 751000 a (ta=room) 5.5 5.7 5.9 v zener voltage vz(ta) iz = 701000 a, full temperature range 5.15 5.7 6.24 v power on reset por level v por_up power-up (full temp range) 1.4 1.75 1.95 v por level v por_down power Cdown (full temp range) 1.3 1.7 1.9 v por hysteresis v por_hys full temp range 0.08 0.1 1.15 v v dd rise time (10% to 90% of specified supply voltage) t por ensure por signal 20 ms output valid (result in ram) tvalid after por 0.25 s pulse width modulation 1 pwm resolution pwmres data band 10 bit pwm output period pwm t,def factory default, internal oscillator factory calibrated 1.024 ms pwm period stability dpwm t internal oscillator factory calibrated, over the entire operation range and supply voltage -10 +10 % output high level pwm hi i source = 2 ma v dd -0.2 v output low level pwm lo i sink = 2 ma v ss +0.2 v output drive current idrive pwm vout,h = v dd - 0.8v 7 ma output sink current isink pwm vout,l = 0.8v 13.5 ma continued on next page mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 7 of 52 data sheet rev 009 june 29, 2015 parameter symbol test conditions min typ max units smbus compatible 2-wire interface 2 input high voltage v ih (ta, v) over temperature and supply 3 v input low voltage v il (ta, v) over temperature and supply 0.6 v output low voltage v ol over temperature and supply, isink = 2ma 0.2 v scl leakage i scl , leak v scl =4v, ta=+85c 30 a sda leakage i sda , leak v sda =4v, ta=+85c 0.3 a scl capacitance c scl 10 pf sda capacitance c sda 10 pf slave address sa factory default 5a hex wake up request t wake sda low 33 ms smbus request t req scl low 1.44 ms timeout, low t imeout,l scl low 27 33 ms timeout, high t imeout,h scl high 45 55 s acknowledge setup time tsuac(md) 8-th scl falling edg e, master 1.5 s acknowledge hold time thdac(md) 9-th scl falling edge , master 1.5 s acknowledge setup time tsuac(sd) 8-th scl falling edge , slave 2.5 s acknowledge hold time thdac(sd) 9-th scl falling edge, slave 1.5 s eeprom data retention ta = +85c 10 years erase/write cycles ta = +25c 100,000 times erase/write cycles ta = +125c 10,000 times erase cell time terase 5 ms write cell time twrite 5 ms table 3: electrical specification mlx90614axx notes: all the communication and refresh rate timin gs are given for the nominal calibrated hfo frequen cy and will vary with this frequencys variations. 1. with large capacitive load lower pwm frequency i s recommended. thermal relay output (when configured) has the pwm dc specification and can be programmed as push-pull, or nmos open drain. pwm i s free-running, power-up factory default is smbus, re fer to section 8.6, switching between pwm and smbu s communication for more details. 2. for smbus compatible interface on 12v applicatio n refer to application information section. smbus compatible interface is described in details in the smbus detailed description section. maximum number of mlx90614 devices on one bus is 127, higher pull-up currents are recommended for higher number of devic es, faster bus data transfer rates, and increased react ive loading of the bus. mlx90614 is always a slave device on the bus. mlx90 614 can work in both low-power and high-power smbus communication. all voltages are referred to the vss (ground) unles s otherwise noted. sleep mode is not available on the 5v version (mlx9 0614axx). mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 8 of 52 data sheet rev 009 june 29, 2015 7.2 mlx90614bxx, mlx90614dxx all parameters are valid for t a = 25 ?c, v dd =3v (unless otherwise specified) parameter symbol test conditions min typ max units supplies external supply v dd 2.6 3 3.6 v supply current i dd no load 1.3 2 ma supply current (programming) i ddpr no load, erase / write eeprom operations 1.5 2.5 ma sleep mode current isleep no load 1 2.5 5 a sleep mode current isleep full temperature range 1 2 .5 6 a power on reset por level v por_up power-up (full temp range) 1.4 1.75 1.95 v por level v por_down power Cdown (full temp range) 1.3 1.7 1.9 v por hysteresis v por_hys full temp range 0.08 0.1 1.15 v v dd rise time (10% to 90% of specified supply voltage) t por ensure por signal 20 ms output valid tvalid after por 0.25 s pulse width modulation 1 pwm resolution pwmres data band 10 bit pwm output period pwm t,def factory default, internal oscillator factory calibrated 1.024 ms pwm period stability dpwm t internal oscillator factory calibrated, over the entire operation range and supply voltage -10 +10 % output high level pwm hi i source = 2 ma v dd -0.25 v output low level pwm lo i sink = 2 ma v ss +0.25 v output drive current idrive pwm vout,h = v dd - 0.8v 4.5 ma output sink current isink pwm vout,l = 0.8v 11 ma continued on next page mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 9 of 52 data sheet rev 009 june 29, 2015 parameter symbol test conditions min typ max units smbus compatible 2-wire interface 2 input high voltage v ih (ta,v) over temperature and supply vdd-0.1 v input low voltage v il (ta,v) over temperature and supply 0.6 v output low voltage v ol over temperature and supply, isink = 2ma 0.25 v scl leakage i scl ,leak v scl =3v, ta=+85c 20 a sda leakage i sda ,leak v sda =3v, ta=+85c 0.25 a scl capacitance c scl 10 pf sda capacitance c sda 10 pf slave address sa factory default 5a hex wake up request t wake sda low 33 ms smbus request t req scl low 1.44 ms timeout,low t imeout,l scl low 27 33 ms timeout, high t imeout,h scl high 45 55 s acknowledge setup time tsuac(md) 8-th scl falling edg e, master 1.5 s acknowledge hold time thdac(md) 9-th scl falling edge , master 1.5 s acknowledge setup time tsuac(sd) 8-th scl falling edge , slave 2.5 s acknowledge hold time thdac(sd) 9-th scl falling edge, slave 1.5 s eeprom data retention ta = +85c 10 years erase/write cycles ta = +25c 100,000 times erase/write cycles ta = +125c 10,000 times erase cell time terase 5 ms write cell time twrite 5 ms table 4: electrical specification mlx90614bxx, dxx note: refer to mlx90614axx notes. mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 10 of 52 data sheet rev 009 june 29, 2015 8 detailed description 8.1 block diagram figure 3: block diagram 8.2 signal processing principle the operation of the mlx90614 is controlled by an i nternal state machine, which controls the measurements and calculations of the object and amb ient temperatures and does the post-processing of t he temperatures to output them through the pwm output or the smbus compatible interface. the assp supports 2 ir sensors (second one not impl emented in the mlx90614xax).the output of the ir sensors is amplified by a low noise low offset c hopper amplifier with programmable gain, converted by a sigma delta modulator to a single bit stream and fe d to a powerful dsp for further processing. the sig nal is treated by programmable (by means of eeprom contend ) fir and iir low pass filters for further reductio n of the band width of the input signal to achieve the d esired noise performance and refresh rate. the outp ut of the iir filter is the measurement result and is availab le in the internal ram. 3 different cells are avail able: one for the on-board temperature sensor and 2 for the ir se nsors. based on results of the above measurements, the cor responding ambient temperature ta and object temperatures to are calculated. both calculated tem peratures have a resolution of 0.01?c. the data for ta and to can be read in two ways: reading ram cells dedic ated for this purpose via the 2-wire interface (0.0 2c resolution, fixed ranges), or through the pwm digit al output (10 bit resolution, configurable range). in the last step of the measurement cycle, the meas ured ta and to are rescaled to the desired output resolution of the pwm) and the recalculated data is loaded in the registers of the pwm state machine, which creates a constant frequency with a duty cycle repr esenting the measured data. 81101 opa adc dsp pwm state machine t voltage regulator 90302 mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 11 of 52 data sheet rev 009 june 29, 2015 8.3 block description 8.3.1 amplifier a low noise, low offset amplifier with programmable gain is used for amplifying the ir sensor voltage. by carefully designing the input modulator and bala nced input impedance, the max offset of the system is 0.5 v. 8.3.2 supply regulator and por the module can operate from 3 different supplies: vdd = 5v mlx90614axx vdd = 3.3v mlx90614bxx (battery or regulated supply) vdd = 816v mlx90614axx few external components are necessary please refer to applications information section for information about adopting higher voltage supplies. the power on reset (por) is connected to vdd supply . the on-chip por circuit provides an active (high) level of the por signal when the vdd voltage rises above approximately 0.5v and holds the entire mlx90614 in reset until the vdd is higher than the specified po r threshold v por . during the time por is active, the por signal is available as an open drain at the pwm/sda pin. after the mlx90614 exits the por condition, t he function programmed in eeprom takes precedence for that pin. 8.3.3 eeprom a limited number of addresses in the eeprom memory can be changed by the customer. the whole eeprom can be read through the smbus interface. eeprom (32x16) name address write access to max 0x00 yes to min 0x01 yes pwmctrl 0x02 yes ta range 0x03 yes emissivity correction coefficient 0x04 yes config register1 0x05 yes melexis reserved 0x06 no melexis reserved 0x0d no smbus address (lsbyte only) 0x0e yes melexis reserved 0x0f yes melexis reserved 0x10 no melexis reserved 0x18 no melexis reserved 0x19 yes melexis reserved 0x1a no melexis reserved 0x1b no id number 0x1c no id number 0x1d no id number 0x1e no id number 0x1f no table 5: eeprom table the addresses to max , to min and ta range are for customer dependent object and ambient temperature ranges. for details see section 8.5.3 below in this document the address emissivity contains the object emissivity (factory default 1. 0 = 0xffff), 16 bit. emissivity = dec2hex[ round( 65535 x ) ] where dec2hex[ round( x ) ] represents decimal to h exadecimal conversion with round-off to nearest val ue (not truncation). in this case the physical emissivity v alues are = 0.11.0. erase (write 0) must take place before write of des ired data is made. mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 12 of 52 data sheet rev 009 june 29, 2015 pwm period configuration: period in extended pwm mo de is twice the period in single pwm mode. in single pwm mode period is t = 1.024*p [ms], wher e p is the number, written in bits 159 pwmctrl. maximum period is then 131.072 ms for single and 26 2.144 ms for extended. these values are typical and depend on the on-chip rc oscillator absolute value. the duty cycle must be calculated instead of worki ng only with the high time only in order to avoid errors fr om the period absolute value deviations. the address pwmctrl consists of control bits for configuring the pwm/s da pin as follows: * values are valid for nominal hfo frequency table 6: pwm control bits the address configregister1 consists of control bits for configuring the analo g and digital parts: note: the following bits / registers should not be altered (except with special tools C contact melexi s for such tools availability) in order to keep the factory ca libration relevant: ke [15...0]; config register1 [14...11;7;3]; addres ses 0x0f and 0x19. table 7: configuration register 1 check www.melexis.com for latest application notes with details on eepro m settings. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 pwm control bit meaning 0 - pwm extended mode 1 - pwm single mode 0 - pwm mode disabled (en_pwm) 1 - pwm mode enabled (en_pwm) 0 - sda pin configured as open drain (ppodb) 1 - sda pin configured as push-pull (ppodb) 0 - pwm mode selected (trpwmb) 1 - thermal relay mode selected (trpwmb) - pwm repetition number 062 step 2 - pwm period 1.024*ms (single pwm mode) or 2.048*m s (extendet pwm mode) multiplied by the number written in this place (128 in case the number is 0) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 config register bit meaning 1 0 0 - iir (100%) a1=1, b1=0 1 0 1 - iir (80%) a1=0.8, b1=0.2 1 1 0 - iir (67%) a1=0.666, b1=0.333 1 1 1 - iir (57%) a1=0.571, b1=0.428 0 0 0 - iir (50%) a1=0.5, b1=0.5 0 0 1 - iir (25%) a1=0.25, b1=0.75 0 1 0 - iir (17%) a1=0.166(6), b1=0.83(3) 0 1 1 - iir (13%) a1=0.125, b1=0.875 0 - repeat sensor test "off" 1 - repeat sensor test "on" 0 0 - ta, tobj1 0 1 - ta, tobj2 1 0 - tobj2 1 1 - tobj1, tobj2 0 - single ir sensor 1 - dual ir sensor 0 - positive sign of ks 1 - negative sign of ks 0 0 0 - fir = 8 not recommended 0 0 1 - fir = 16 not recommended 0 1 0 - fir = 32 not recommended 0 1 1 - fir = 64 not recommended 1 0 0 - fir = 128 1 0 1 - fir = 256 1 1 0 - fir = 512 1 1 1 - fir = 1024 0 0 0 - gain = 1 - amplifier is bypassed 0 0 1 - gain = 3 0 1 0 - gain = 6 0 1 1 - gain = 12,5 1 0 0 - gain = 25 1 0 1 - gain = 50 1 1 0 - gain = 100 1 1 1 - gain = 100 0 - positive sign of kt2 1 - negative sign of kt2 0 - enable sensor test 1 - disable sensor test mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 13 of 52 data sheet rev 009 june 29, 2015 on-chip filtering and settling time: the mlx90614 features configurable on-chip digital filters. they allow customization for speed or nois e. factory default configurations and the typical sett ling time and noise for the mlx90614 family are giv en below. device settling time, sec typical noise, c rms spike limit mlx90614aaa, baa, daa 0.10 0.05 100% mlx90614aba, bba 0.14 0.07 100% mlx90614acc, bcc, dcc 0.14 0.18 100% mlx90614acf, bcf 1.33 0.10 50% mlx90614dch, dci, bch, bci 0.65 0.10 80% table 8: factory default iir and fir configuration, settling time and typical noise details on the filters are given in the application note understanding mlx90614 on-chip digital signa l filters available from www.melexis.com . the evaluation board, evb90614 supported by pc sw a llows easy configuration of the filters, while not requiring in-depth understanding of the eeprom. the available filter settings and the settling time s are listed below. settling time depends on three configurations: single / dual zone, iir filter sett ings and fir filter settings. the fir filter has a straight forward effect on noise (4 times decreasing of filter stren gth increases the noise 2 times and vice versa. the iir filter provides an additional, spike limiting feature. spi ke limit defines the level of magnitude to which th e spike would be limited C for example, 25% denotes that if a 20 c temperature delta spike is measured the temperatu re reading by the mlx90614 will spike only 5c. table 9: possible iir and fir settings note: settling time is in seconds and depends on in ternal oscillator absolute value. 100% spike limit appears with the iir filter bypass ed, and there is no spike limitation. settling time (s) settling time (s) 90614xax 90614xbx, 90614xcx xxx 000011 100 100 0.04 0.06 100.00% 100 101 0.05 0.07 100.00% 100 110 0.06 0.10 100.00% 100 111 0.10 0.14 100.00% 101 100 0.12 0.20 80.00% 101 101 0.16 0.24 80.00% 101 110 0.22 0.34 80.00% 101 111 0.35 0.54 80.00% 110 100 0.24 0.38 66.70% 110 101 0.30 0.48 66.70% 110 110 0.43 0.67 66.70% 110 111 0.70 1.10 66.70% 111 100 0.26 0.42 57.00% 111 101 0.34 0.53 57.00% 111 110 0.48 0.75 57.00% 111 111 0.78 1.20 57.00% 000 100 0.30 0.47 50.00% 000 101 0.37 0.60 50.00% 000 110 0.54 0.84 50.00% 000 111 0.86 1.33 50.00% 001 100 0.70 1.10 25.00% 001 101 0.88 1.40 25.00% 001 110 1.30 2.00 25.00% 001 111 2.00 3.20 25.00% 010 100 1.10 1.80 16.70% 010 101 1.40 2.20 16.70% 010 110 2.00 3.20 16.70% 010 111 3.30 5.00 16.70% 011 100 1.50 2.40 12.50% 011 101 1.90 3.00 12.50% 011 110 2.80 4.30 12.50% 011 111 4.50 7.00 12.50% not recommended fir setting iir setting spike limit mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 14 of 52 data sheet rev 009 june 29, 2015 8.3.4 ram it is not possible to write into the ram memory. i t can only be read and only a limited number of ram registers are of interest to the customer. ram (32x17) name address read access melexis reserved 0x 00 yes melexis reserv ed 0x 0 3 yes raw data ir channel 1 0x 0 4 raw data ir channel 2 0x0 5 t a 0x06 yes t obj1 0x07 yes t obj2 0x08 yes melexis reserved 0x0 9 yes melexis reserved 0x 1f yes table 10: ram addresses 8.4 smbus compatible 2-wire protocol the chip supports a 2 wires serial protocol, build with pins pwm / sda and scl. scl C digital input only, used as the clock for sm bus compatible communication. this pin has the auxiliary function for building an external voltage regulator. when the external voltage regulator is used, the 2-wire protocol is available only if the power supply regulator is overdriven. pwm / sda C digital input / output, used for both the pwm output of the measured object temperature(s) or the digital input / output for th e smbus. in pwm mode the pin can be programmed in eeprom to operate as push / pull or open drain nmos (open drain nmos is factory default). in smbus mode sda is forced to open drain nmos i/o, pu sh-pull selection bit defines pwm / thermal relay operation. smbus communication with mlx90614 is covered in det ails in application notes, available from www.melexis.com . 8.4.1 functional description the smbus interface is a 2-wire protocol, allowing communication between the master device (md) and one or more slave devices (sd). in the system o nly one master can be presented at any given time [ 1]. the mlx90614 can only be used as a slave device. generally, the md initiates the start of data trans fer by selecting a sd through the slave address (sa ). the md has read access to the ram and eeprom and wr ite access to 9 eeprom cells (at addresses 0x00, 0x01, 0x02, 0x03, 0x04, 0x05*, 0x0e, 0x0f, 0x 09). if the access to the mlx90614 is a read operat ion it will respond with 16 data bits and 8 bit pec only i f its own slave address, programmed in internal eep rom, is equal to the sa, sent by the master. the sa feature allows connecting up to 127 devices (sa=0x000x07f ) with only 2 wires, unless the system has some of th e specific features described in paragraph 5.2 of r eference [1]. in order to provide access to any device or to assign an address to a sd before it is connected t o the bus system, the communication must start with zero sa f ollowed by low r/w bit. when this command is sent from the md, the mlx90614 will always respond and will i gnore the internal chip code information. special care must be taken not to put two mlx90614 devices with the same sa on the same bus as mlx90614 does not support arp [1]. the md can force the mlx90614 into low consumption mode sleep mode (3v version only). read flags like eebusy (1 C eeprom is busy with e xecuting the previous write/erase), ee_dead (1 C there is fatal eeprom error and this chip is not fu nctional**). mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 15 of 52 data sheet rev 009 june 29, 2015 note*: this address is readable and writable. bit 3 should not be altered as this will cancel the fact ory calibration. note**: eeprom error signaling is implemented in au tomotive grade parts only. 8.4.2 differences with the standard smbus specifica tion (reference [1]) there are eleven command protocols for standard smb us interface. the mlx90614 supports only two of them. not supported commands are: quick command byte commands - sent byte, receive byte, write byt e and read byte process call block commands C block write and write-block read process call supported commands are: read word write word 8.4.3 detailed description the pwm / sda pin of mlx90614 can operate also as p wm output, depending on the eeprom settings. if pwm is enabled, after por the pwm / sd a pin is directly configured as pwm output. even if the device is in pwm mode smbus communication may be re stored by a special command. that is why hereafter both modes are treated separately. 8.4.3.1 bus protocol figure 4: smbus packet element key after every received 8 bits the sd should issue ack or nack. when a md initiates communication, it first sends the address of the slave and only the s d which recognizes the address will ack, the rest w ill remain silent. in case the sd nacks one of the bytes, the md should stop the communication and repeat the message. a nack could be received after the pec. th is means that there is an error in the received mes sage and the md should try sending the message again. th e pec calculation includes all bits except the star t, s wr slave address a data byte a p s start condition sr repeated start condition rd read (bit value of 1) wr write (bit value of 0) a acknowledge (this bit can be 0 for ack and 1 for na ck) s stop condition pec packet error code master-to-slave slave-to-master 1 1 7 1 8 1 1 mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 16 of 52 data sheet rev 009 june 29, 2015 repeated start, stop, ack, and nack bits. the pec i s a crc-8 with polynomial x8+x2+x1+1. the most significant bit of every byte is transferred f irst. 8.4.3.1.1 read word (depending on the command C ram or eeprom) figure 5: smbus read word format 8.4.3.1.2 write word (depending on the command C ra m or eeprom) figure 6: smbus write word format 8.4.4 bit transfer figure 7: recommended timing on smbus scl sampling data sda changing data s wr slave address a data byte low a p command a sr slave address rd 1 7 1 1 8 1 1 7 1 8 1 1 .. .. a 1 data byte high a 8 1 pec a 8 1 s wr slave address a data byte low a p command a 1 7 1 1 8 1 8 1 1 .. .. data byte high a 8 1 pec a 8 1 mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 17 of 52 data sheet rev 009 june 29, 2015 the data on pwm / sda must be changed when scl is l ow (min 300ns after the falling edge of scl). the data is fetched by both md and sds on the risin g edge of the scl. the recommended timing for chang ing data is in the middle of the period when the scl is low. 8.4.5 commands ram and eeprom can be read both with 32x16 sizes. i f the ram is read, the data are divided by two, due to a sign bit in ram (for example, t o1 - ram address 0x07 will sweep between 0x27ad to 0 x7fff as the object temperature rises from -70.01c to +382.19c ). the msb read from ram is an error flag (active h igh) for the linearized temperatures (t o1 , t o2 and t a ). the msb for the raw data (e.g. ir sensor1 data) is a sign bit (sign and magnitude format). a write of 0x0000 must be done prior to writing in eeprom in order to era se the eeprom cell content. refer to eeprom detailed descr iption for factory calibration eeprom locations tha t need to be kept unaltered. opcode command 000x xxxx* ram access 001x xxxx* eeprom access 1111_0000** read flags 1111_1111 enter sleep mode table 11: smbus commands note*: the xxxxx represent the 5 lsbits of the memo ry map address to be read / written. note**: behaves like read command. the mlx90614 ret urns pec after 16 bits data of which only 4 are meaningful and if the md wants it, it can stop the communication after the first byte. the difference between read and read flags is that the latter does not hav e a repeated start bit. flags read are: data[7] - eebusy - the previous write/erase eeprom access i s still in progress. high active. data[6] - unused data[5] - ee_dead - eeprom double error has occurred. high active. data[4] - init - por initialization routine is still ongoing. low active. data[3] - not implemented. data[2...0] and data[8...15] - all zeros. flag read is a diagnostic feature. the mlx90614 can be used regardless of these flags. for details and examples for smbus communication wi th the mlx90614 check the www.melexis.com 8.4.6 smbus communication examples figure 8: read word format (sa=0x5a, read ram=0x07, result=0x3ad2, pec=0x30) figure 9: write word format (sa=0x5a, write eeprom= 0x02, data=0xc807, pec=0x48) scl sda 1 0 1 1 0 1 0 0a 0 0 0 0 1 1 1 a s s 0 1 1 0 1 0 a 1 a a p sa_w = 0xb4 command = 0x07 r w 1 0 1 0 0 1 1 0 0 1 1 1 0 1 0 0 0 1 1 0 0 0 0 0 a lsbyte = 0xd2 msbyte = 0x3a pec = 0x30 sa_r = 0xb5 scl sda 1 0 1 1 0 1 0 0a 0 1 0 0 0 1 0 a s 0 0 0 0 1 1 a 0 a a p command = 0x22 1 w 1 0 0 1 0 0 1 0 1 0 0 1 0 0 0 0 msbyte = 0xc8 pec = 0x48 lsbyte = 0x07 sa_w = 0xb4 mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 18 of 52 data sheet rev 009 june 29, 2015 8.4.7 timing specification the mlx90614 meets all the timing specifications of the smbus [1]. the maximum frequency of the mlx90614 smbus is 100 khz and the minimum is 10 khz . the specific timings in mlx90614s smbus are: smbus request ( t req ) is the time that the scl should be forced low in order to switch mlx90614 from pwm mode to smbus mode C at least 1.44ms; timeout l is the maximum allowed time for scl to be low during communication. after this time the mlx90614 will reset its communication block and wil l be ready for new communication C not more than 27 ms; timeout h is the maximum allowed time for scl to be high during communication. after this time mlx90614 will reset its communication block assumin g that the bus is idle (according to the smbus specification) C not more than 45 s. tsuac(sd) is the time after the eighth falling ed ge of scl that mlx90614 will force pwm / sda low to acknowledge the last received byte C not more than 2,5 s. thdac(sd) is the time after the ninth falling edg e of scl that mlx90614 will release the pwm / sda (so the md can continue with the communication) C n ot more than 1,5 s. tsuac(md) is the time after the eighth falling ed ge of scl that mlx90614 will release pwm / sda (so that the md can acknowledge the last received byte) C not more than 1,5 s. thdac(md) is the time after the ninth falling edg e of scl that mlx90614 will take control of the pwm / sda (so it can continue with the next byte to trans mit) C not more than 1,5 s. the indexes md and sd for the latest timings are used C md when the master device is making acknowledge; sd when the slave device is making ack nowledge. for other timings see [1]. figure 10: smbus timing specification and definitio n scl sda timeout_l > 27ms timeout_h > 45s 1 2 3 4 5 6 7 8 9 1 0 1 0 1 0 1 1 ack tsuac thdac md < 1.5s sd < 2.5s md < 1.5s sd < 1.5s mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 19 of 52 data sheet rev 009 june 29, 2015 8.4.8 sleep mode the mlx90614 can enter in sleep mode via the comman d enter sleep mode sent via the smbus interface. this mode is not available for the 5v su pply version. there are two ways to put mlx90614 in to power-up default mode: - por - by wake up request scl pin high and then pwm/sda pin low for at least t ddq > 33ms if eeprom is configured for pwm (en_pwm is high), t he pwm interface will be selected after awakening and if pwm control [2], ppodb is 1 the ml x90614 will output a pwm pulse train with push- pull output. note: in order to limit the current consumption to the typical 2.5 a melexis recommends that the scl pin is kept low during sleep as there is leakage current t rough the internal synthesized zener diode connecte d to scl pin. this may be achieved by configuring the md dri ver of scl pin as push-pull and not having pull-up resistor connected on scl line. 8.4.8.1 enter sleep mode figure 11: enter sleep mode command (sa = 0x5a, com mand = 0xff, pec = 0xe8) 8.4.8.2 exit from sleep mode (wake up request) figure 12: exit sleep mode after wake up the first data is available after 0.2 5 seconds (typ). on-chip iir filter is skipped for the very first measurement. all measurements afterwards pass the embedded digital filtering as configured in ee prom. details on embedded filtering are available in appl ication note understanding mlx90614 on-chip digita l signal filters, available from www.melexis.com scl sda 1 0 1 1 0 1 0 1 a 1 1 1 1 1 1 1 a s 1 1 0 1 0 0 a 1 p command = 0xff 0 w pec = 0xe8 sa_w = 0xb4 normal operation mode sleep mode sda scl > 33ms sleep mode normal mode mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 20 of 52 data sheet rev 009 june 29, 2015 8.4.9 mlx90614 smbus specific remarks the auxiliary functions of the scl pin (zener diode ) add undershoot to the clock pulse (5v devices only) as shown in the picture below (see figure 13) . this undershoot is caused by the transient respon se of the on-chip synthesized zener diode. typical duration o f undershoot is approximately 15 s. an increased reactance of the scl line is likely to increase this effect. undershoot does not affect the recognition of the s cl rising edge by the mlx90914, but may affect proper operation of non-mlx90614 slaves on the same bus. figure 13: undershoot of scl line due to on chip sy nthesized zener diode (5v versions only) continuous smbus readings can introduce and error. as the scl line inside to39 package is passing relatively close to the sensor input and error sign al is induced to the sensor output. the manifestati on of the problem is wrong temperature readings. this is espe cially valid for narrow fov devices. possible solut ion is to keep sda and scl line quiet for period longer than refresh rate and settling time defined by internal settings of mlx90614 prior reading the temperature or switch to pwm signal and completely disconnect from sda and scl line. mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 21 of 52 data sheet rev 009 june 29, 2015 8.5 pwm the mlx90614 can be read via pwm or smbus compatibl e interface. selection of pwm output is done in eeprom configuration (factory default is smbus). pwm output has two programmable formats, single an d dual data transmission, providing single wire readi ng of two temperatures (dual zone object or object and ambient). the pwm period is derived from the on-chi p oscillator and is programmable. config register[5:4] pwm1 data pwm2 data tmin,1 tmax,1 tmin,2 tmax,2 00 t a t o 1 t a_r ange ,l t a_r ange ,h t o _min t o _max 01 t a t o 2 t a_ra nge ,l t a_r ange ,h t o _min t o _max 11 t o 1 t o 2 t o _min t o _max t o _min t o _max 10* t o 2 undefined t o _min t o _max n.a. n.a. table 12: pmw configuration table note: serial data functions (2-wire / pwm) are mult iplexed with a thermal relay function (described in the thermal relay section). * not recommended for extended pwm format operation figure 14: pwm timing single (above) and extended p wm (bellow) pwm type t1 t2 t3 t4 t5 t6 t7 t8 single 1/8 C high 4/8 - var 2/8 1/8 C low na na na na extended - s1 1/16 - high 4/16 - var 2/16 1/16 - lo w 1/16 - low 4/16 C low 2/16 - low 1/16 - low extended - s2 1/16 - high 4/16 - high 2/16 - high 1 /16 - high 1/16 - high 4/16 - var 2/16 1/16 - low table 13: pmw timing t1 t2 t3 t4 fe valid data band error band start stop 0 t 5 8 t 1 8 t 13 16 t 7 8 t t1 t2 t3 t4 fe sensor 1 error band start stop 0 t 1 16 t t 5 16 t 7 16 t 8 16 valid data band t5 t6 sensor 1 t7 fe error band sensor 2 sensor 2 valid data band t8 t 9 16 t 13 16 t 15 16 mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 22 of 52 data sheet rev 009 june 29, 2015 8.5.1 single pwm format in single pwm output mode the settings for pwm1 dat a only are used. the temperature reading can be calculated from the signal timing as: ( ) min o min o max o out t t t t t t _ _ _ 2 2 + ?? ? ?? ? - = where tmin and tmax are the corresponding rescale c oefficients in eeprom for the selected temperature output (ta, object temperature range is valid for b oth tobj1 and tobj2 as specified in the previous ta ble) and t is the pwm period. tout is t o1 , t o2 or t a according to config register [5:4] settings. the different time intervals t 1 t 4 have following meaning: t 1 : start buffer. during this time the signal is alwa ys high. t 1 = 0.125s x t (where t is the pwm period, please refer to figure 14). t 2 : valid data output band, 01/2t. pwm output data r esolution is 10 bit. t 3 : error band C information for fatal error in eepro m (double error detected, not correctable). t 3 = 0.25s x t. therefore a pwm pulse train with a du ty cycle of 0.875 will indicate a fatal error in ee prom (for single pwm format). fe means fatal error. example: figure 15: pwm example single mode c t min o = 0 _ ( ) ( ) 3 6 0 27315 15. 273 100 01 0, _ _ ab x d t x eeprom t min o min o = = + = c t max o = 50 _ ( ) ( ) b e x d t x eeprom t max o max o 3 7 0 32315 15. 273 100 00 0, _ _ = = + = captured pwm period is t = 1004 s captured high duration is t = 392 s calculated duty cycle is: 3904 .0 1004 392 = = = t t d or % 04.39 the temperature is calculated as follows: ( ) ( ) c t o = = + - - = 54.26 50 2654 .0 2 0 0 50 125.0 3904 .0 2 mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 23 of 52 data sheet rev 009 june 29, 2015 8.5.2 extended pwm format the pwm format for extended pwm is shown in figure 16. note that with bits dual[5:1]>0x00 each period will be outputted 2n+1 times, where n is the decimal value of the number written in dual[5:1] ( dual[5:1] =pwm control & clock [8:4] ), like shown on figure 16. figure 16: extended pwm format with dual [5:1] = 01 h (2 repetitions for each data) the temperature transmitted in data 1 field can be calculated using the following equation: ( ) 1 1 1 2 1 4 min min max out t t t t t t + ?? ? ?? ? - = for data 2 field the equation is: ( ) 2 2 2 5 2 4 min min max out t t t t t t + ?? ? ?? ? - = time bands are: t 1 =0.0625 x t (start1), t 3 =0.125 x t and t 4 =0.5625 x t (start2 = start1 + valida_data1 + error_band1 + stop1 + start2). as shown in figure 13, in extended pwm format the period is twice the period for the single pwm format. all equations provided h erein are given for the single pwm period t. the ee prom error band signaling will be 43.75% duty cycle for data1 and 93.75% for data2. note: eeprom error signaling is implemented in auto motive grade parts only. figure 17: example: extended pwm mode readings C s ensor 1 above and sensor 2 bellow t3 t1 t2 start 0 t 1 16 t t 8 16 t 15 16 t=16.875ms t=100ms (pwm = 10hz) t1 t2 start 0 t 1 16 t t 8 16 t 15 16 t=73.125ms t=100ms (pwm = 10hz) extended pwm mode sensor 1 extended pwm mode sensor 2 mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 24 of 52 data sheet rev 009 june 29, 2015 example: (see figure 17 above): configuration: sensor1 = ta, sensor2 = t obj1 config reg[5:4] = 00b, c t min a = 0 _ ( ) ( ) c x d t eeprom t a l range a 3 0 60 6875 .59 64 2.38 100 min_ _ _ = ? = + = c t max a = 60 _ ( ) ( ) 99 0 153 4375 . 153 64 2.38 100 max_ _ _ x d t eeprom t a h range a = ? = + = ( ) { } c x t t x eeprom t l range a h range a range a 993 0 : 03 0, _ _ _ _ _ = = c t min o = 0 _ ( ) ( ) 3 6 0 27315 15. 273 100 01 0, min_ _ ab x d t x eeprom t o min o = = + = c t max o = 50 _ ( ) ( ) b e x d t x eeprom t o max o 3 7 0 32315 15. 273 100 00 0, min_ _ = = + = captured high durations are: sensor 1 C t = 16.875ms at period t = 100ms thus th e duty cycle is 16875 .0 100 875.16 1 = = s duty sensor 2 C t = 73.125ms at period t = 100ms thus th e duty cycle is 73125 .0 100 125.73 2 = = s duty the temperatures are calculated as follows: ( ) ( ) min a min a max a s a t t t start duty t _ _ _ 1 1 4 + - - = ( ) ( ) c t a = + - - = 5.25 0 0 60 0625 .0 16875 .0 4 ( ) ( ) min o min o max o s o t t t start duty t _ _ _ 2 1 2 4 + - - = ( ) ( ) c t o = + - - = 75.33 0 0 50 5625 .0 73125 .0 4 1 8.5.3 customizing the temperature range for pwm out put the calculated ambient and object temperatures are stored in ram with a resolution of 0.01c (16 bit). the pwm operates with a 10-bit word so the transmit ted temperature is rescaled in order to fit in the desired range. for this goal 2 cells in eeprom are foreseen to sto re the desired range for to (to min and to max ) and one for ta (ta range : the 8msb are foreseen for ta max and the 8lsb for ta min ). thus the output range for to can be programmed with an accuracy of 0.01c, while the corresponding ta range can be programmed with an accuracy of 0.64c. the object data for pwm is rescaled according to th e following equation: 1023 , eeprom eeprom eeprom obj min max obj pwm obj pwm min ram pwm t t k k t t t - = - = mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 25 of 52 data sheet rev 009 june 29, 2015 the t ram is the linearized tobj, 16-bit (0x00000xffff, 0x0 000 for -273.15c and 0xffff for +382.2c) and the result is a 10-bit word, in which 0x000 corresponds to to min [c], 0x3ff corresponds to to max [c] and 1lsb corresponds to 1023 min max to to - [c]. 100 = min min t t eeporm lsb 100 = max max t t eeporm lsb the ambient data for pwm is rescaled according to t he following equation: ambient eeprom ambient pwm min ram pwm k t t t - = where: 1023 eeprom eeprom min max ambient pwm t t k - = the result is a 10-bit word, where 0x000 correspond s to -38.2c (lowest ta that can be read via pwm), 0x3ff corresponds to 125c (highest ta that can be read via pwm) and 1lsb corresponds to: [ ] c t t lsb min max - = , 1023 1 ( ) ( ) 64 100 2.38 - - = min min t t eeporm lsb ( ) ( ) 64 100 2.38 - - = max max t t eeporm lsb mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 26 of 52 data sheet rev 009 june 29, 2015 8.6 switching between pwm / thermal relay and smbus communication 8.6.1 pwm is enabled the diagram below illustrates the way of switching to smbus if pwm / thermal relay is enabled (factory programmed por default for mlx90614 is smb us, pwm disabled). note that the scl pin needs to b e kept high in order to use pwm. figure 18: switching from pwm mode to smbus 8.6.2 request condition figure 19: request (switch to smbus) condition if pwm / thermal relay is enabled, the mlx90614s s mbus request condition is needed to disable pwm / thermal relay and reconfigure pwm/sda pin bef ore starting smbus communication. once pwm / thermal relay is disabled, it can be only enabled b y switching the supply off C on or exit from sleep mode. the mlx90614s smbus request condition requires for cing low the scl pin for period longer than the req uest time (t req >1,44ms). the sda line value is ignored and is irr elevant in this case. 8.6.3 pwm is disabled if pwm is disabled by means of eeprom the pwm / sda pin is directly used for the smbus purposes after por. request condition should not be sent in this case . scl pwm/sda start stop t req pwm mode smbus mode >1.44ms scl smbus request t req >1,44ms mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 27 of 52 data sheet rev 009 june 29, 2015 8.7 computation of ambient and object temperatures the ir sensor consists of serial connected thermo-c ouples with cold junctions placed at thick chip substrate and hot junctions, placed over thin membr ane. the ir radiation absorbed from the membrane he ats (or cools) it. the thermopile output signal is: ( ) ( ) 4 4 , ta to a to ta v ir - = where to is the absolute object temperature (kelvin ), ta is the sensor die absolute (kelvin) temperature, and a is the overall sensitivity. an on board temperature sensor is needed to measure the chip temperature. after measurement of the output of both sensors, the corresponding ambient a nd object temperatures can be calculated. these calculations are done by the internal dsp, which pr oduces digital outputs, linearly proportional to me asured temperatures. 8.7.1 ambient temperature ta the sensor die temperature is measured with a ptat element. all the sensors conditioning and data processing is handled on-chip and the linearized se nsor die temperature ta is available in memory. the resolution of the calculated temperature is 0.0 2?c. the sensor is factory calibrated for the full automotive range -40+125?c. the linearized die tem perature is available in ram cell 0x06: - 0x06=0x2de4 (11748d) corresponds to -38.2?c (line arization output lower limit) - 0x06=0x4dc4 (19908d) corresponds to +125?c. (line arization output higher limit) the conversions from ram contend to real ta is easy using the following relation: 02.0 ] [ = tareg k ta , or 0.02k / lsb. 8.7.2 object temperature to the result has a resolution of 0.02 ?c and is avail able in ram. to is derived from ram as: 02.0 ] [ = toreg k to , or 0.02k / lsb. please note that 1lsb corresponds to 0,02 and the msb bit is error flag (if 1 then error). example: 1. 0x27ad -70.00?c (no error) 2. 0x27ae -69.98?c (no error) 3. 0x3af7 28.75?c (no error) 4. 0x3af8 28.77?c (no error) 5. 0x7fff 382.19?c (no error) - maximum possible value retu rned by mlx90614 6. 0x8xxx xxx.xx?c (flag error) the result is calculated by following expressions ( valid for both to and ta): 1. convert it to decimal value i.e. 0x3af7 = 15095d 2. divide by 50 (or multiply by 0.02) i.e. 9. 301 50 15095 = k (result is in kelvin) 3. convert k -> ?c i.e. 301.9 - 273.15 = 28.75?c mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 28 of 52 data sheet rev 009 june 29, 2015 8.7.3 calculation flow the measurement, calculation and linearization are held by core, which executes a program form rom. after por the chip is initialized with calibration data from eeprom. during this phase the number of i r sensors is selected and it is decided which tempera ture sensor will be used. measurements, compensatio n and linearization routines run in a closed loop afterwa rds. processing ambient temperature includes : offset measurement with fixed length fir filter additional filtering with fixed length iir filter. the result is stored into ram as t os temperature sensor measurement using programmable length fir *. offset compensation additional processing with programmable length iir **. the result is stored into ram as t d . calculation of the ambient temperature. the result is stored into ram address 0x06 as t a processing of the object temperature consists of th ree parts. the first one is common for both ir sensors, the th ird part can be skipped if only one ir sensor is us ed. ir offset : offset measurement with a fixed length fir additional filtering with a fixed length iir. the result is stored into ram as ir os . gain measurement with fixed length fir filter offset compensation additional gain filtering with fixed length iir, storing the result into ram as ir g . gain compensation calculation, the result is stor ed into ram as k g object temperature: ir1 sensor : ir sensor measurement with programmable length fi r filter *. offset compensation gain compensation filtering with programmable length iir filter**, storing the result into ram address 0x04 as ir1 d . calculation of the object temperature. the result is available in ram address 0x07 as t o1 . ir2 sensor : ir sensor measurement with programmable length fi r filter *. offset compensation gain compensation filtering with programmable length iir filter**, storing the result into ram address 0x05 as ir2 d calculation of the object temperature. the result is available in ram address 0x08 as t o2 pwm calculation: recalculate the data for pwm with 10 bit resolutio n load data into pwm module note*: the measurements with programmable filter le ngth for fir filter use the same eeprom cells for n . note**: the iir filter with programmable filter len gth uses the same eeprom cells for l. mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 29 of 52 data sheet rev 009 june 29, 2015 figure 20: software flow initialization t a offset meas os ta = meas(n tos ) filtering t os = iir(l tos ,os ta ) t a meas t data = meas(n ta ) offset comp t datacomp = t data -t os filtering t d = iir(l ta ,t datacomp ) t a calculation t a ir offset meas os ir = meas(n iros ) filtering ir os = iir(l iros ,os ir ) ir1 meas ir1 d = meas(n ir ) offset comp ir1 dcomp = ir1 d - ir os filtering ir1 d = iir(l ir ,ir1 dg ) t obj1 calculation gain drift ir gm = meas(n irg ) offset comp ir gcomp = ir gm - ir os filtering ir g = iir(l g ,ir gcomp ) k g calculation ir offset gain comp ir1 dg = ir1 dcomp *k g ir2 meas ir2 d = meas(n ir ) offset comp ir2 dcomp = ir2 d - ir os filtering ir2 d = iir(l ir ,ir2 dg ) t obj2 calculation gain comp ir2 dg = ir2 dcomp *k g t obj1 t obj2 pwm calculation load pwm registers 1 1 2 3 2 3 mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 30 of 52 data sheet rev 009 june 29, 2015 8.8 thermal relay the mlx90614 can be configured to behave as a therm o relay with programmable threshold and hysteresis on the pwm/sda pin. the input for the c omparator unit of the relay is the object temperatu re from sensor 1 the output of the mlx90614 is not a relay driver bu t a logical output which should be connected to a relay driver if necessary. the output driver is one and the same for pwm and t hermal relay. in order to configure the mlx90614 to work as therm al relay two conditions must be met: o set bit trpwmb high at address 0x02 in eeprom o enable pwm output i.e. en_pwm is set high the pwm / sda pin can be programmed as a push-pull or open drain nmos (via bit ppodb in eeprom pwmctrl), which can trigger an external devi ce. the temperature threshold data is determined by eeprom at address 0x21 (to min ) and the hysteresis at address 0x020 (to max ). the logical state of the pwm/sda pin is as follows: pwm / sda pin is high if hysteresis threshold t o + 3 1 pwm / sda pin is low if hysteresis threshold t o - 1 figure 21: thermal relay: pwm pin versus tobj the mlx90614 preserves its normal operation when co nfigured as a thermal relay (pwm configuration and specification applies as a general rule also fo r the thermal relay) and therefore it can be read u sing the smbus (entering the smbus mode from both pwm and th ermal relay configuration is the same). for example, the mlx90614 can generate a wake-up al ert for a system upon reaching a certain temperature and then be read as a thermometer. rese t conditions (enter and exit sleep, for example) wi ll be needed in order to return to the thermal relay conf iguration. example: c threshold = 5 ( ) ( ) 7 6 0 27815 15. 273 100 01 0, ca x d threshold x eeprom = = + = c hysteresis = 1 ( ) 0064 0 100 100 00 0, x d hysteresis x eeprom = = = smallest possible hysteresis is 0,01c or (eeprom, 0x00 = 0x0001) pwm / sda pin will be set low at object temperature below 4c pwm / sda pin will be set high at object temperatur e higher that 6c threshold hysteresis hysteresis t 0 1 mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 31 of 52 data sheet rev 009 june 29, 2015 9 unique features the mlx90614 is a ready-to use low-cost non contac t thermometer provided from melexis with output data linearly dependent on the object temperature w ith high accuracy and extended resolution. the high thermal stability of the mlx90614-xcx mak e this part highly suited in applications where secondary heat sources can heat up the sensor. the se sensors also have a very short stabilization time compared to other types of thermopile sensors, which is of importance if one needs an accurate measurement in conditions where the ambient tempera ture can change quickly. the mlx90614 supports versatile customization to a very wide range of temperatures, power supplies and refresh rates. the user can program the internal object emissivit y correction for objects with a low emissivity. an embedded error checking and correction mechanism pr ovides high memory reliability. the sensors are housed in an industry standard to3 9 package for both single- and dual-zone ir thermometers. the thermometer is available in autom otive grade and can use two different packages for wider applications coverage. the low power consumption during operation and the low current draw during sleep mode make the thermometer ideally suited for handheld mobile appl ications. the digital sensor interface can be either a power -up-and-measure pwm or an enhanced access smbus compatible protocol. systems with more than 1 00 devices can be built with only two signal lines. dual zone non contact temperature measureme nts are available via a single line (extended pwm). a build-in thermal relay function further extends the easy implementation of wide variety of freezing/boiling prevention and alert systems, as w ell as thermostats (no mcu is needed). mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 32 of 52 data sheet rev 009 june 29, 2015 10 performance graphs 10.1 temperature accuracy of the mlx90614 10.1.1 standard accuracy all accuracy specifications apply under settled iso thermal conditions only. furthermore, the accuracy is only valid if the object fills the fov of the sensor com pletely. figure 22: accuracy of mlx90614 (ta, to) all accuracy specifications apply under settled iso thermal conditions only. -70 -20 0 ta, o c 50 100 125 -40 -40 0 60 120 180 240 300 380 to, o c 1 o c 1 o c 1 o c 1 o c 2 o c 3 o c 2 o c 2 o c 3 o c 3 o c 2 o c 3 o c 3 o c 4 o c 4 o c 4 o c 3 o c 4 o c 3 o c 2 o c 1 o c 1 o c 2 o c 2 o c 2 o c 2 o c 3 o c 0.5 o c mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 33 of 52 data sheet rev 009 june 29, 2015 10.1.2 medical accuracy a version of the mlx90614 with accuracy suited for medical applications is available. the accuracy in the range ta 16c40c and to 22c40c is shown in diagram below. the accuracy for the rest of the temperature ranges is the same as in previous diagr am. medical accuracy specification is only availabl e for the mlx90614dxx versions. figure 23: accuracy of mlx90614daa (ta, to) for med ical applications. accuracy of the mlx90614dcc, dch and dci for vdd = 3v (see paragraph 10.1.3) versions mlx90614esf-dcc, -dch and -dci comply with astm standard section 5.4 (designation: e1965 C 98 (re-approved 2009) - standard specificat ion for infrared thermometers for intermittent determination of patient temperature it is very important for the application design to understand that the accuracy specified in figure 22 and figure 23 are only guaranteed when the sensor is in thermal equilibrium and under isothermal condition s (there are no temperature differences across the sensor pa ckage). the accuracy of the thermometer can be influenced by temperature differences in the packag e induced by causes like (among others): hot electr onics (heaters / coolers) behind or beside the sensor or when the measured object is so close to the sensor that heats the thermometer package. this effect is especially relevant for thermometers with a small field of view (fov) like the xxc and xxf as the energy received by the sensor from the o bject is reduced. therefore, melexis has introduce d the xcx version of the mlx90614. in these mlx90614xcx, the thermal gradients are measured internally and the measured temperature is compensated for them. in t his way, the mlx90614xcx is much less sensitive to thermal gradients induced from outside, but the eff ect is not totally eliminated. it is therefore imp ortant to avoid introducing strong heat sources close to the sensor or to shield the sensor from them. note: in order to have the highest possible signal and t he best performance a higher gain of the amplifier is selected for mlx90614dcx type of devic es. this eventually would limit the maximum object temperature (due to overload of the adc) to about 2 00c. 10.1.3 temperature reading dependence on v dd in case of medical applications where high accuracy is required and the supply is provided by means of a battery, a compensation of temperature readings f rom vdd dependence should be done by the microcontroller. the dependence is very repeatable and compensation can easily be implemented. as this 0.3c 10 0.2c 36 38 40 20 30 40 0.3c to, c ta, c 20 30 22 mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 34 of 52 data sheet rev 009 june 29, 2015 dependence comes from the ambient temperature it is the same for all type of devices regardless of fov and optics used and it directly translates in the same compensation for object temperature. the typical vdd dependence of the ambient and objec t temperature is 0.6c/v. figure 24: typical ta dependence from supply voltag e example: as the devices are calibrated at vdd=3v th e error at vdd=3v is smallest one. the error in amb ient channel is directly transferred as object channel e rror (see figure 25 bellow). figure 25: typical to dependence from supply voltag e (practically the same as ta dependence error in order to compensate for this error we measure su pply voltage and by applying following equation compensate the result. 6.0 )3 ( _ ) ( 0 _ - - = - - = vdd t dependence typical vdd vdd t t o o d compensate o figure 26: typical to compensated dependence error typical ta=f(vdd) dependance -0.50 -0.40 -0.30 -0.20 -0.10 0.00 0.10 0.20 0.30 0.40 0.50 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 vdd, v ta error, degc sensor1 sensor2 sensor3 sensor4 sensor5 sensor6 sensor7 sensor8 sensor9 sensor10 sensor11 sensor12 sensor13 sensor14 sensor15 sensor16 typical to=f(vdd) dependance -0.50 -0.40 -0.30 -0.20 -0.10 0.00 0.10 0.20 0.30 0.40 0.50 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 vdd, v to error, degc sensor1 sensor2 sensor3 sensor4 sensor5 sensor6 sensor7 sensor8 sensor9 sensor10 sensor11 sensor12 sensor13 sensor14 sensor15 sensor16 compensated vdd dependence -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 vdd, v to_compensated error, degc sensor1 sensor2 sensor3 sensor4 sensor5 sensor6 sensor7 sensor8 sensor9 sensor10 sensor11 sensor12 sensor13 sensor14 sensor15 sensor16 mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 35 of 52 data sheet rev 009 june 29, 2015 10.2 field of view (fov) figure 27: field of view measurement parameter mlx90614xaa mlx90614xba mlx90614xcc mlx90614xcf mlx90614xch mlx90614xci peak zone 1 0 +25 0 0 0 0 width zone 1 90 70 35 10 12 5 peak zone 2 not applicable -25 not applicable not applicable not applicable not ap plicable width zone 2 70 table 14: fov summary table figure 28: typical fov of mlx90614xaa 0.00 0.25 0.50 0.75 1.00 -80 -60 -40 -20 0 20 40 60 80 angle, deg point heat source rotated sensor angle of incidence 100% 50% sensitivity field of view mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 36 of 52 data sheet rev 009 june 29, 2015 figure 29: typical fov of mlx90614xba figure 30: id entification of zone 1&2 relative to alignment tab figure 31: typical fov of mlx90614xcc 0.00 0.25 0.50 0.75 1.00 -80 -60 -40 -20 0 20 40 60 80 angle, deg 0.00 0.25 0.50 0.75 1.00 -80 -60 -40 -20 0 20 40 60 80 angle , de g mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 37 of 52 data sheet rev 009 june 29, 2015 figure 32: typical fov of mlx90614xcf figure 33: typical fov of mlx90614xch 0.00 0.25 0.50 0.75 1.00 -80 -60 -40 -20 0 20 40 60 80 angle, de g 0.00 0.25 0.50 0.75 1.00 -80o -60o -40o -20o 0o 20o 40o 60o 80o angle, deg mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 38 of 52 data sheet rev 009 june 29, 2015 figure 34: typical fov of mlx90614xci 0.00 0.25 0.50 0.75 1.00 -80o -60o -40o -20o 0o 20o 40o 60o 80o angle, deg mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 39 of 52 data sheet rev 009 june 29, 2015 11 applications information 11.1 use of the mlx90614 thermometer in smbus confi guration figure 35: mlx90614 smbus connection figure 35 shows the connection of a mlx90614 to a s mbus with 3.3v power supply. the mlx90614 has diode clamps sda / scl to vdd so it is necessar y to provide mlx90614 with power in order not to lo ad the smbus lines. 11.2 use of multiple mlx90614s in smbus configurati on figure 36: use of multiple mlx90614 devices in smbu s network the mlx90614 supports a 7-bit slave address in eepr om, thus allowing up to 127 devices to be read via two common wires. with the mlx90614xbx this res ults in 254 object temperatures measured remotely a nd an additional 127 ambient temperatures which are al so available. current source pull-ups may be prefer red with higher capacitive loading on the bus (c3 and c4 rep resent the lines parasitic), while simple resistiv e pull-ups provide the obvious low cost advantage. scl vz vdd r2 2 c1 0.1uf 3 u1 mcu scl sda gnd vdd 4 +3.3v p w m sda u2 mlx90614bxx r1 1 smbus vss r2 u1 mlx90614bxx 4 1 2 scl vz u1 mlx90614bxx c4 cbus2 u1 mcu scl sda gnd vdd 1 i1 ipu1 c2 0.1uf scl vz 3 sda c3 cbus1 r1 3 scl 4 c1 0.1uf vss +3.3v i2 ipu2 vdd vdd 2 smbus vss current source or resistor pull-ups of the bus p w m sda p w m sda mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 40 of 52 data sheet rev 009 june 29, 2015 11.3 pwm output operation using the pwm output mode of the mlx90614 is very s imple, as shown in figure 37. figure 37: connection of mlx90614 for pwm output mo de the pwm mode is free-running after por when configu red in eeprom. the scl pin must be forced high for pwm mode operation (can be shorted to v dd pin). a pull-up resistor can be used to preserve the opti on for smbus operation while having pwm as a default as is shown on figure 38. figure 38: pwm output with smbus available again, the pwm mode needs to be written as the por default in eeprom. then for pwm operation the scl line can be high impedance, forced high, or even not connected. the pull-up resistor r1 will e nsure there is a high level on the scl pin and the pwm po r default will be active. smbus is still available (for example C for further reconfiguration of the mlx906 14, or sleep mode power management) as there are pu ll-up resistors on the smbus lines anyway. pwm can be configured as open drain nmos or a push- pull output. in the case of open drain external pull-up will be needed. this allows cheap level con version to lower logic high voltage. internal pull- ups present in many mcus can also be used. 11.4 thermal alert / thermostat figure 39: thermal alert / thermostat applications of mlx90614 j1 con1 pwm vdd gnd 2 0.1uf vdd u1 mlx90614 vss p w m sda 1 c1 scl vz 3 p w m sda 10k 3 1 vdd 2 r1 scl vz j1 con1 scl pwm/sda gnd vdd u1 mlx90614 vss 0.1uf c1 u2 ac line r1 3 c2 10uf c1 0.1uf u1 mcu scl sda gnd vdd 2 scl vz c* 2 scl vz u1 mlx90614axx u1 mlx90614bxx vss vdd 1 1 smbus r2 vdd 4 q1 4 1 +5v u1 mlx90614axx vdd vss +3.3v r1 c3 0.1uf scl vz 3 r2 +24v vss c1 0.1uf pw m sda pw m sda 3 4 p w m sda d1 alert dev ice + - 2 mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 41 of 52 data sheet rev 009 june 29, 2015 the mlx90614 can be configured in eeprom to operate as a thermal relay. a non contact freezing or boiling prevention with 1 ma quiescent current can be built with two components only C the mlx90614 an d a capacitor. the pwm / sda pin can be programmed as a push-pull or open drain nmos, which can trigger an external device, such as a relay (refer to electric al specifications for load capability), buzzer, rf transmitter or a led. this feature allows very simple thermostats to be built without the need of any mcu and zero desi gn overhead required for firmware development. in conj unction with a mcu, this function can operate as a system alert that wakes up the mcu. both object temperatur e and sensor die temperature can also be read in th is configuration. 11.5 high voltage source operation as a standard, the module mlx90614axx works with a supply voltage of 5volt. in addition, thanks to the integrated internal reference regulator availab le at pin scl / vz, this module can easily be power ed from higher voltage source (like vdd=816v). only a few external components as depicted in the diagram bel ow are required to achieve this. figure 40: 12v regulator implementation with the second (synthesized zener diode) function of the scl / vz pin used, the 2-wire interface function is available only if the voltage regulator is overdriven (5v regulated power is forced to vdd pin). 2.2uf 1 vdd vss pw m sda u1 5.7v c* +12v j1 con1 pwm v+ gnd 3 equivalent schematics q1 q1 u1 mlx90614 2 c1 scl vz mlx90614axx: v=8...16v +5v 4 r1 r1 mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 42 of 52 data sheet rev 009 june 29, 2015 12 application comments significant contamination at the optical input side (sensor filter) might ca use unknown additional filtering/distortion of the optical signal and ther efore result in unspecified errors. ir sensors are inherently susceptible to errors cau sed by thermal gradients . there are physical reasons for these phenomena and, in spite of the ca reful design of the mlx90614, it is recommended not to subject the mlx90614 to heat transfer and especiall y transient conditions. upon power-up the mlx90614 passes embedded checking and calibrat ion routines. during these routines the output is not defined and it is recomm ended to wait for the specified por time before rea ding the module. very slow power-up may cause the embedded p or circuitry to trigger on inappropriate levels, re sulting in unspecified operation and this is not recommende d. the mlx90614 is designed and calibrated to operate as a non contact thermometer in settled conditions . using the thermometer in a very different way wil l result in unknown results. capacitive loading on a smbus can degrade the communication. some improvement is possible with use of current sources compared to resistors in pul l-up circuitry. further improvement is possible wit h specialized commercially available bus accelerators . with the mlx90614 additional improvement is possi ble by increasing the pull-up current (decreasing the pull -up resistor values). input levels for smbus compat ible mode have higher overall tolerance than the smbus specif ication, but the output low level is rather low eve n with the high-power smbus specification for pull-up currents . another option might be to go for a slower commun ication (clock speed), as the mlx90614 implements schmidt t riggers on its inputs in smbus compatible mode and is therefore not really sensitive to rise time of the bus (it is more likely the rise time to be an issue than the fall time, as far as the smbus systems are open drain wi th pull-up). for esd protection there are clamp diodes between the vss and vdd and each of the other pins. this means that the mlx90614 might draw current from a b us in case the scl and/or sda is connected and the vdd is lower than the bus pull-ups voltage. in 12v powered systems smbus usage is constrained because the scl pin is used for the zener diode function. applications where the supply is hi gher than 5v should use the pwm output or an extern al regulator. nevertheless, in the 12v powered applica tions mlx90614 can be programmed (configured and customized) by forcing the vdd to 5v externally and running the smbus communication. a sleep mode is available in the mlx90614bxx. this mode is ente red and exited via the smbus compatible 2-wire communication. on the other hand, the extended functionality of the scl pin yields i n increased leakage current through that pin. as a re sult, this pin needs to be forced low in sleep mode and the pull-up on the scl line needs to be disabled in ord er to keep the overall power drain in sleep mode re ally small. during sleep mode the sensor will not perform measu rements. the pwm pin is not designed for direct drive of inducti ve loads (such as electro-magnetic relays). some drivers need to be implemented for higher load , and auxiliary protection might be necessary even for light but inductive loading. it is possible to use the mlx90614 in applications, powered directly from the ac line (transformer les s). in such cases it is very important not to forget th at the metal package of the sensor is not isolated and therefore may occur to be connected to that line, t oo. melexis can not be responsible for any applicat ion like this and highly recommends not using the mlx90614 in tha t way. power dissipation within the package may affect performance in two w ays: by heating the ambient sensitive element significantly beyond the actual a mbient temperature, as well as by causing gradients over the package that will inherently cause thermal gradient over the cap. loading the outputs also causes incr eased power dissipation. in case of using the mlx90614axx internal zener voltage feature, the regulating ext ernal transistor should also not cause heating of the to3 9 package. mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 43 of 52 data sheet rev 009 june 29, 2015 high capacitive load on a pwm line will result in significant charging currents from the power supply, bypassing the capacitor and therefore causing emc, noise, level degradation and power dissipation prob lems. a simple option is adding a series resistor between the pwm / sda pin and the capacitive loaded line, in which case timing specifications have to be carefully rev iewed. for example, with a pwm output that is set t o 1.024 ms and the output format that is 11 bit, the time s tep is 0.5 s and a settling time of 2 s would introduce a 4 lsb error. power supply decoupling capacitor is needed as with most integrated circui ts. mlx90614 is a mixed- signal device with sensors, small signal analog par t, digital part and i/o circuitry. in order to keep the noise low power supply switching noise needs to be decoupled. high noise from external circuitry can also affect noise performance of the device. in many applications a 1 00nf smd ceramic capacitor close to the vdd and vss pins would be a good choice. it should be noted that not only the trace to the vdd pin needs to be short, b ut also the one to the vss pin. using mlx90614 with short pins improves the effect of the power supply decoupling. severe noise can also be coupled within the package from the scl (in worst cases also from the sda) pi n. this issue can be solved by using pwm output. also the p wm output can pass additional filtering (at lower p wm frequency settings). with a simple lpf rc network a dded also increase of the esd rating is possible. check www.melexis.com for most recent application notes about mlx90614. mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 44 of 52 data sheet rev 009 june 29, 2015 13 standard information regarding manufacturability of melexis products with different soldering processes our products are classified and qualified regarding soldering technology, solderability and moisture s ensitivity level according to following test methods: wave soldering thds (through hole devices) eia/jedec jesd22-b106 and en60749-15 resistance to soldering temperature for through-hol e mounted devices iron soldering thds (through hole devices) en60749-15 resistance to soldering temperature for through-hol e mounted devices solderability thds (through hole devices) eia/jedec jesd22-b102 and en60749-21 solderability for all soldering technologies deviating from above mentioned standard conditions (regarding peak temperature, temperature gradient, temperature prof ile etc) additional classification and qualificatio n tests have to be agreed upon with melexis. melexis is contributing to global environmental con servation by promoting lead free solutions. for more information on qualifications of rohs compliant products (rohs = european directive on t he restriction of the use of certain hazardous substances) please visit t he quality page on our website: http://www.melexis.com/quality.aspx the mlx90614 is rohs compliant 14 esd precautions electronic semiconductor products are sensitive to electro static discharge (esd). always observe electro static discharge control pro cedures whenever handling semiconductor products. mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 45 of 52 data sheet rev 009 june 29, 2015 15 faq when i measure aluminum and plastic parts settled a t the same conditions i get significant errors on aluminum. why? different materials have different emissivity . a typical value for aluminum (roughly polished) i s 0.18 and for plastics values of 0.840.95 are typical. ir thermo meters use the radiation flux between the sensitive element in the sensor and the object of interest, given by the equation ( ) ( ) 2 4 2 2 1 4 1 1 1 a t f a t q ba - = - s e s a e , where: 1 and 2 are the emissivities of the two objects, 1 is the absorptivity of the sensor (in this case), is the stefan-boltzmann constant, a 1 and a 2 are the surface areas involved in the radiation he at transfer, f a-b is the shape factor, t 1 and t 2 are known temperature of the sensor die (measured with specially integrated and calibrated element) and the object temperature that we need. note that these are all in kelvin, heat exchange kn ows only physics. when a body with low emissivity (such as aluminum) is involved in this heat transfer, the portion of t he radiation incident to the sensor element that reall y comes from the object of interest decreases C and the reflected environmental ir emissions take place. (t his is all for bodies with zero transparency in the ir band.) the ir thermometer is calibrated to stay within spe cified accuracy C but it has no way to separate the incoming ir radiation into real object and reflected environ mental part. therefore, measuring objects with low emissivity is a very sophisticated issue and infra-red measure ments of such materials are a specialized field. what can be done to solve that problem? look at pai ntings C for example, oil paints are likely to have emissivity of 0.850.95 C but keep in mind that the stability of the paint emissivity has inevitable i mpact on measurements. it is also a good point to keep in mind that not ev erything that looks black is black also for ir. f or example, even heavily oxidized aluminum has still e missivity as low as 0.30. how high is enough? not an easy question C but, in all cases the closer you need to get to the real object temperature the higher the needed emissivity will be, of course. with the real life emissivity values the environmen tal ir comes into play via the reflectivity of the object (the sum of emissivity, reflectivity and absorptivi ty gives 1.00 for any material). the larger the dif ference between environmental and object temperature is at given reflectivity ( with an opaque for ir material reflectivity equals 1.00 minus emissivity ) the bigger errors it produces. after i put the mlx90614 in the dashboard i start g etting errors larger than specified in spite that the module was working properly before that. why? any object present in the fov of the module provide s ir signal. it is actually possible to introduce e rror in the measurements if the module is attached to the dashb oard with an opening that enters the fov. in that c ase portion of the dashboard opening will introduce ir signal in conjunction with constraining the effecti ve fov and thus compromising specified accuracy. relevant open ing that takes in account the fov is a must for acc urate measurements. note that the basic fov specification takes 50% of ir signal as threshold (in order to d efine the area, where the measurements are relevant), while t he entire fov at lower level is capable of introduc ing lateral ir signal under many conditions. when a hot (cold) air stream hits my mlx90614 some error adds to the measured temperature i read. what is it? ir sensors are inherently sensitive to difference i n temperatures between the sensitive element and ev erything incident to that element. as a matter of fact, this element is not the sensor package, but the sensor die inside. therefore, a thermal gradient over the sensor packa ge will inevitably result in additional ir flux bet ween the sensor package and the sensor die. this is real opt ical signal that can not be segregated from the tar get ir signal and will add errors to the measured temperat ure. mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 46 of 52 data sheet rev 009 june 29, 2015 thermal gradients with impact of that kind are like ly to appear during transient conditions. the senso r used is developed with care about sensitivity to this kind of lateral phenomena, but their nature demands some care when choosing place to use the mlx90614 in order to make them negligible. i measure human body temperature and i often get me asurements that significantly differ from the +37c i expect. ir measurements are true surface temperature measur ements. in many applications this means that the ac tual temperature measured by an ir thermometer will be t emperature of the clothing and not the skin tempera ture. emissivity (explained first in this section) is ano ther issue with clothes that has to be considered. there is also the simple chance that the measured t emperature is adequate C for example, in a cold win ter human hand can appear at temperatures not too close to the well known +37c. i consider using mlx90614aaa to measure temperature within car compartment, but i am embarrassed about the sun light that may hit the mo dule. is it a significant issue? special care is taken to cut off the visible light spectra as well as the nir (near ir) before it reac hes the sensitive sensor die. even more, the glass (in most cases) is not transparent to the ir radiation used by the mlx90614. glass has temperature and really high emi ssivity in most cases C it is black for ir of int erest. overall, sun behind a window is most likely to intr oduce relatively small errors. why is it not comple tely eliminated after all? even visible light partially absorbed in the filter of the sensor has some heati ng potential and there is no way that the sensor die will be bl ind for that heating right in front of it. mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 47 of 52 data sheet rev 009 june 29, 2015 16 package information 16.1 mlx90614xxa the mlx90614 is packaged in an industry standard to 39 can. figure 41: mlx90614xxa package note: all dimensions are in mm 16.2 mlx90614xcc figure 42: mlx90614xcc package mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 48 of 52 data sheet rev 009 june 29, 2015 16.3 mlx90614xcf figure 43: mlx90614xcf package 16.4 mlx90614xch figure 44: mlx90614xch package mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 49 of 52 data sheet rev 009 june 29, 2015 16.5 mlx90614xci figure 45: mlx90614xci package 16.6 part marking the mlx90614 is laser marked with 10 symbols. first 3 letters define device version (aaa, bcc, etc), a nd the last 7 are the lot number. example: acc9307308 C mlx90614acc from lot 9307308. 16.7 operating and storage humidity range operating and storage humidity range is defined as 85% non condensing humidity. mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 50 of 52 data sheet rev 009 june 29, 2015 17 table of figures figure 1: typical application schematics .......... ................................................... ................................................... 1 figure 2: pin description ......................... ................................................... ................................................... ...........5 figure 3: block diagram ........................... ................................................... ................................................... ...... 10 figure 4: smbus packet element key................. ................................................... ............................................... 15 figure 5: smbus read word format .................. ................................................... ................................................. 1 6 figure 6: smbus write word format ................. ................................................... .................................................. 16 figure 7: recommended timing on smbus ............. ................................................... ......................................... 16 figure 8: read word format (sa=0x5a, read ram=0x07, result=0x3ad2, pec=0x30) ......................... ............ 17 figure 9: write word format (sa=0x5a, write eeprom= 0x02, data=0xc807, pec=0x48) ...................... .......... 17 figure 10: smbus timing specification and definitio n.................................................. ......................................... 18 figure 11: enter sleep mode command (sa = 0x5a, com mand = 0xff, pec = 0xe8) .......................... ........... 19 figure 12: exit sleep mode ........................ ................................................... ................................................... .... 19 figure 13: undershoot of scl line due to on chip sy nthesized zener diode (5v versions only) .......... ............... 20 figure 14: pwm timing single (above) and extended p wm (bellow) ....................................... ............................ 21 figure 15: pwm example single mode ................ ................................................... ............................................. 22 figure 16: extended pwm format with dual [5:1] = 01 h (2 repetitions for each data) ................... ................... 23 figure 17: example: extended pwm mode readings C s ensor 1 above and sensor 2 bellow ................. .......... 23 figure 18: switching from pwm mode to smbus ....... ................................................... ...................................... 26 figure 19: request (switch to smbus) condition .... ................................................... .......................................... 26 figure 20: software flow .......................... ................................................... ................................................... ....... 29 figure 21: thermal relay: pwm pin versus tobj ... ................................................... ......................................... 30 figure 22: accuracy of mlx90614 (ta, to) .......... ................................................... ............................................ 32 figure 23: accuracy of mlx90614daa (ta, to) for med ical applications. accuracy of the mlx90614dch and dci for vdd = 3v (see paragraph 10.1.3) ........... ................................................... ...................................... 33 figure 24: typical ta dependence from supply voltag e ................................................. ..................................... 34 figure 25: typical to dependence from supply voltag e (practically the same as ta dependence error .... ........ 34 figure 26: typical to compensated dependence error ................................................... .................................... 34 figure 27: field of view measurement .............. ................................................... ............................................... 35 figure 28: typical fov of mlx90614xaa ............. ................................................... ........................................... 35 figure 29: typical fov of mlx90614xba ............. ................................................... ........................................... 36 figure 30: identification of zone 1&2 relative to a lignment tab ...................................... ...................................... 36 figure 31: typical fov of mlx90614xcc ............. ................................................... ........................................... 36 figure 32: typical fov of mlx90614xcf ............. ................................................... ........................................... 37 figure 33: typical fov of mlx90614xch ............. ................................................... ........................................... 37 figure 34: typical fov of mlx90614xci ............. ................................................... ............................................ 38 figure 35: mlx90614 smbus connection .............. ................................................... ........................................... 39 figure 36: use of multiple mlx90614 devices in smbu s network ......................................... ............................. 39 figure 37: connection of mlx90614 for pwm output mo de ................................................ ............................... 40 figure 38: pwm output with smbus available ........ ................................................... .......................................... 40 figure 39: thermal alert / thermostat applications of mlx90614 ....................................... ................................. 40 figure 40: 12v regulator implementation ........... ................................................... ............................................... 41 figure 41: mlx90614xxa package .................... ................................................... ............................................... 47 figure 42: mlx90614xcc package .................... ................................................... .............................................. 47 figure 43: mlx90614xcf package..................... ................................................... .............................................. 48 figure 44: mlx90614xch package .................... ................................................... .............................................. 48 figure 45: mlx90614xci package .................... ................................................... ................................................ 49 mlx90614 family single and dual zone infra red thermometer in to-39 3901090614 page 51 of 52 data sheet rev 009 june 29, 2015 18 references [1] system management bus (smbus) specification version 2.0 august 3, 2000 sbs implementers forum copyright . 1994, 1995, 1998 , 2000 duracell, inc., energizer power systems, inc., fuji tsu, ltd., intel corporation, linear technology inc., maxim integrated products, mitsubishi electri c semiconductor company, powersmart, inc., toshiba battery co. ltd., unitrode corporation, usa r systems, inc. 19 disclaimer devices sold by melexis are covered by the warranty and patent indemnification provisions appearing in its term of sale. melexis makes no warranty, expres s, statutory, implied, or by description regarding the information set forth herein or regarding the freed om of the described devices from patent infringemen t. melexis reserves the right to change specifications and pri ces at any time and without notice. therefore, prio r to designing this product into a system, it is necessa ry to check with melexis for current information. t his product is intended for use in normal commercial applicatio ns. applications requiring extended temperature ran ge, unusual environmental requirements, or high reliabi lity applications, such as military, medical life-s upport or life- sustaining equipment are specifically not recommend ed without additional processing by melexis for eac h application. the information furnished by melexis is believed to be correct and accurate. however, melexis shall no t be liable to recipient or any third party for any dama ges, including but not limited to personal injury, property damage, loss of profits, loss of use, interrupt of business or indirect, special incidental or consequ ential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the t echnical data herein. no obligation or liability to recipien t or any third party shall arise or flow out of mel exis rendering of technical or other services. ? 2015 melexis nv. all rights reserved. for the latest version of this document, go to our website at www.melexis.com or for additional information contact melexis direc t: europe, africa, asia: america: phone: +32 1367 0495 phone: +1 248 306 5400 e-mail: sales_europe@melexis.com e-mail: sales_usa @melexis.com iso/ts 16949 and iso14001 certified |
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