circuit note cn- 0287 circuits from the lab? reference designs are engineered and tested for quick and easy system integration to help solve todays analog, mixed - signal, and rf design challenges. for more i nformation and/or support , visit www.analog.com/cn0287 . devices connected /referenced ad 7193 4 - cha nnel, 4.8 khz, ultralow noise, 24- bit sigma - delta adc with pga adt7310 0.5c accurate, 16 - bit digital spi temperature sensor ad 8603 precision micropower, low noise cmos r -to - r input/output operational amplifiers ad r3440 4.096 v, micropower high accuracy voltage reference adg738 cmos, low voltage, 3 - wire serially - controlled, matrix switch adg702 cmos low voltage 2 spst switch ad 5201 33 - position digital potentiometer adum1280 3 kv rms dual channel digital isolators adum5401 quad - channel, 2.5 kv isolators with integrated dc - to - dc converter isolated 4 - channel, thermocouple/rtd temperature measurement system with 0.5c accuracy rev. c circuits from the lab? reference designs from analog devices have been designed and built by analog devices engineers. standard engineering practices have been employed in the design and construction of each circuit, and their function and performance have been tested and verified in a lab environment at room temperature. however, you are solely responsible for testing the circuit and determining its suitability and applicability for your use and application. accordingly, in no event shall analog devices be liable for direct, indirect, special, incidental, consequential or punitive damages due to any cause whatsoever connected to the use of any circuits from the lab circuits. (continued on last page) one technology way, p.o. box 9106, norwood, ma 02062 - 9106, u.s.a. tel: 781.329.4700 www.analog.com fax: 781.461.3113 ? 2013 C 2014 analog devices, inc. all rights reserved. evaluation and desig n support circuit evaluation boards cn - 02 87 circuit evaluation board ( eval - cn0287 - sdpz ) system demonstration platform ( eva l - sdp - cb1z ) design and integration files schematics, layout files, bill of materials circuit function and benefits the circuit shown in f igure 1 is a complete ly isolated 4 - channel temperature measurement circuit optimized for performance, input flexibility , robustness , and low cost. it support s all type s of thermocouple s with cold junction compensation and any type of rtd ( resistance temperature detector ) with r esistance s up to 4 k ? for 2 - , 3 - , or 4 - wire connection configurations. the rtd excitation current are is programmable for optimum noise and linearity performance. rtd measurements achieve 0.1 c accuracy (typical) , and type - k t hermocouple measurements achieve 0. 0 5 c typical accuracy because of the 16 - bit adt7310 digital temperature sensor used for cold - junction compensation . the circuit uses a four - channel ad 7193 24 - bit sigma - delta adc with on - chip pga for high accuracy and low noise. i nput transient and overvoltage protection are provided by low leakage transient voltage supressors (tvs) and schottky diodes. t he spi - compatible digital inputs and outputs are isolated (2500 v rms) , and the circuit is ope rated on a fully isolated power supply.
cn- 0287 circuit note rev. c | page 2 of 9 f igure 1. 4- channel t hermocouple and rtd c ircuit (s implified s chematic : all c onnections and d ecoupling n ot s hown ) circuit description temperature measurement introduction thermocouple s and rtd s r esistance t emperature d etector s are the most frequently used sensor s for temperature measurement in industrial applications thermocouples are able to measure very high temperatures up to about c and also have a fast response time measured in fractions of a second rtds are capable of higher accuracy and stability than thermocouples and the resistance of long wire lengt hs hundreds of meters to a remote rtd can be compensated for with - or - wire connections a thermocouple consist s of two wires of different metals oined at one end this end is placed at the temperature which is to be measured refered to as the m eas urement unction the other end is connected to a precision voltage measurement unit and this connecti on is referred to as the r eference unction or alternately the c old unction the temperature difference between the measurement unction and the cold u nction generates a voltage known as the seebeck effect voltage that is related to the difference between the temperatures of the two unctions the signal generated is typically from several microvolts to tens of millivolt depending on the temperature difference for eample - type thermocouple s are capable of measuring c to c with an output range of approimately mv to m v it is important for the si gnal chain to maintain as high impedance and low leakage as possible to achieve the highest accuracy for the voltage measurement in order to convert this voltage to an absolute temperature the cold unction temperature must be accurately know n tradition ally c to c has been considered sufficient al though since the cold unction measurement error contributes directly to the absolute temperature error a higher accuracy cold unction temperature measurement is beneficial an rtd is made from a pure mat erial such as platinum nickel or copper that has a predictable change in resistance as the temperature changes the most widely used rtd is p latinum p t and p t ne method used to accurately measure the resistance is to measure the voltage acros s the rtd generated by a constant current source errors in the current source can be cancelled by refer r ing the measurement to the voltage generated across a ad7193 refin2(?) refin2(+) ain8 ain7 ain2 ain1 1.69k ? 1.69k ? 1.69k ? 1.69k ? 1.69k ? +5v 300 ? 300 ? 300 ? 300 ? 300 ? 1.69k ? 300 ? 1.69k ? 300 ? 1.69k ? 300 ? 1.69k ? 300 ? 1nf 1nf +5v +5v 27nf 1nf 1nf +5v +5v +5v +5v +5v +5v 27nf d s in adg702 1k? r3 c2 c2 c2 s1 s2 s7 s8 sclk d din sync adg738 dout pwr-on preset a w b shdn v dd v ss cs clk sdi gnd AD5201 logic contro l +5v +4.096v p2 p3 adr3440 v out force sense force sense gnd +5v refin1(+) refin1(0) +4.096v ad8603 adt7310 sclk dout din ct int sclk dout din ct int cold junction compens a tion sclk gnd cs adt7310_cs sclk din adg738_cs sclk dout din cs sclk dout din ad7193_cs dgnd agnd +5v sclk din +5v +5v v? v+ 0.1f 10f +5v aincom ain4 ain3 ain6 ain5 jp1 1 2 3 1 2 3 1 2 3 4 1 2 3 4 jp4 +5v thermocouple: rtd 2,3w rtd 4w ch 1 ch 4 4.02k ? 0.1% 10ppm +5v 5.6v zener diode 0 ? : analog ground : digi t a l ground dv dd a v dd gnd 1 gnd iso +5v iso v dd1 gnd 2 v dd2 v i a v ib v o a v ob adum 128 0 +5v ct int ct iso int iso gnd iso gnd 2 v dd2 gnd 1 v dd1 v o a v ob v i a v ib +5v iso +5v adum1280 adt7310_cs adg738_cs adt7310_cs iso adg738_cs iso sclk dout din adum5401 ad7193_cs ad7193_cs iso gnd iso din iso sclk iso dout iso gnd iso v dd1 v iso gnd 1 v o a v o a v oc v id v i a v ib v ic v od +5v iso +5v 10926-001
circuit note cn- 0287 rev. c | page 3 of 9 reference resistor that is driven with the same current (i.e. a ratiometric measurement). minimiz ing the leakage current through the current path is important for achieving high accuracy because the excitation current is typically only a few hundred microamps to prevent self heating . for the industrial field application s both high performance as well as protection against both high - voltage transient events and dc over - voltage conditions are important design considerations . how this c ircuit w orks the circuit shown in f igure 1 is designed for precision temperature measurement application s in the industrial field environment and is optimized for flexibility, performance, robustness , and cost. this circuit uses the ad 7193 , low noise, 24- bit sigma - delta adc to ensure high resolution and linearity for the entire circuit. the ad 5201 , 33 - position digital potentiometer , ad 8603 op amp, and adg702 single channel switch constitute a simple programmable current source and bias voltage buffer for the rtd and thermocouple measurement s. the adg738 routes the current source to the active rtd channel and allows wire resistance compensation for the 3 - w rtd configuration . the adt7310 d igital spi t emperature s ensor has 0.8 c maximum accuracy (+5 v supply) from ?40c to +105c and is used for cold - junction compensation for the thermocouple measurement. the ad r3440 is a low noise and high accuracy 4.096 v reference connected to refin 1 ( + ) /refin 1 (?) of the ad 7193 for the thermocouple measurement s. a nalog - to - digital converter the ad 7193 is a low noise, complete analog front end for high precision measurement applications. it contains a low noise, 24 - bit sigma - delta ( - ) analog - to - digital converter (adc). this adc achieves high resolution, low non - linearity , and low noise performance as well as very high 50 hz /60 hz rejection. the dat a output rate can be varied from 4.7 hz (24 bit s effective resolution , g ain = 1 ), to 4.8 khz (18.6 bit s effective resolution , g ain = 1 ). the on - chip low noise pga amplifies the small differential signal from the thermocouple or rtd with a gain programmable from 1 up to 128 , thereby allowing a direct interface. the gain stage buffer has high input impedance and limits the input leakage current to 3 na maximum. the gain of the ad 7193 must be configured properly depending on the temperature range and type of sensors. the on - chip multiplex er allows four differential input channels to be shared with the same adc core, saving both space and cost. programmable current source for rtds and bias voltage generator c ircuit for thermocouples rtd measurements require a low noise current source that drives the rtd and a reference resistor. thermocouple measurement s, on the other h and, need a common - mode bias voltage that shifts the small thermocouple voltage into the input range of the ad 7193. the circuit shown in figure 2 meets both requirements and utilizes the ad 8603 a low noise cmos rail - to - rail input / output op amp with only 1 pa maximum inpu t bias current and 50 v maximum offset voltage , combined with the adg702 single channel, cmos low voltage 2 spst switch , and the adg738 eight - channel matrix switch . figure 2. external programmable c urrent s ource and b ias voltage g enerator with the adg738 opened and the adg702 closed, the ad 8603 act s as a low noise, low output impedance unity - gain buffer for the thermocouple application. the voltage from the ad 5201 digital potentiometer is buffered and is used for the thermocouple common - mode voltage, u sually 2.5 v, which is one - half the supply voltage . the 33- position ad 5201 digital potentiometer is driven with the ad r3440 low drift (5 ppm/c) 4.096 v reference for accuracy. with the adg738 c losed and the adg702 opened, the ad 8603 generates the rtd excitation current, i exc = v w /r ref . ad7193 refin2(?) refin2(+) ain2 ain1 d s adg702 1k? r3 c2 d s1 adg738 a w b AD5201 +4.096v ad8603 +5v rtd tc v w i exc i exc = v w r ref r ref 10926-002
cn- 0287 circuit note rev. c | page 4 of 9 temperature measurement is a high precision and low speed application, therefore there is adequate settling time available to switch the single current source between all 4 channels , providing excellent channel - to - channel matching, low cost, and small pcb footprint. the adg738 is an 8 - to - 1 multiplexer that switches the current source between channels. in order to support the 2 - , 3 - , and 4 - wire rtd configuration s , each of the four channel s need two switches. in man y applications , the rtd may be located remotely from the measurement circuit. the resistance from the long lead wire s can generate large error s , especially for low resistance rtd s. in order to minimize the effect of the lead resistance, a 3 - wire rtd configuration is supported as shown in figure 3 . figure 3. connector and j umper c onfiguration for 3- w ire rtd sensor with s1 of the adg738 closed and s2 opened, t he v oltage at the input of ad 7193 is v 1 . with s1 opened and s2 closed, the voltage on the input of ad 7193 is v 2 , the voltage across the rtd sensor is v rtd , the ex citing current from the current source is i exc . v 1 and v 2 contain the error generated by the lead resistance as shown below: exc w3 rtd 1 i r r v + = ) ( (1) exc w3 rtd w2 2 i r r r v + + = ) ( (2) exc rtd rtd i r v = (3) assuming r w1 = r w2 = r w3 and c ombining equations 1, 2, and 3 yields: v rtd = 2 v 1 C v 2 (4) r rtd = v rtd / i exc = (2 v 1 C v 2 )/ i exc (5) equation 5 shows that the 3 - wire configuration requires two separate measurements (v 1 and v 2 ) in order to calculate r rtd , thereby decreasing the output data rate. in most applications this is not a problem. the 4 - wire rtd connection requires two extra sense lines , but is insensitive to wiring resistances and only requires one measurement . figure 4 summarizes the connector configuration and jumper placements for rtd 2 - wire, rtd 3 - wire, rtd 4 - wire, and thermocouple applications. figure 4. connector c onfiguration and j umper p lacements for eval - cn0287 - sdpz b oard ad7193 refin2(-) refin2() ain2 ain1 s1 d adg738 rtd i ec i ec s2 jpx 5v r rtd r ref r w1 r w2 r w3 crrent sorce 5v 10926-003 r td 2-w i r e r td 3-w i r e r td 4-w i r e t h e r o c o p l e j p x 2 1 3 2 1 3 4 cnx rtd rtd j p x 2 1 3 2 1 3 4 cnx j p x 2 1 3 2 1 3 4 cnx j p x 2 1 3 2 1 3 4 cnx tc rtd 10926-004
circuit note cn- 0287 rev. c | page 5 of 9 protection circuit s transient and overvoltage conditions are possible both during manufacturing and in the field. to achieve a high level of protection, additional external protection circuitry is necessary to compliment the ics internal integrated protection circuitry. the external protection adds additional capacitance, resistance , and leakage . t hese effects should be carefully considered to achieve a high level of accuracy. the additional protection circuitry is shown in figure 5 . figure 5. transient and o vervoltage p rotection c ircuit leakage currents can have a significant effect on rtd measurements so should be carefully considered. leakage current s can also create some error in t hermocouple measurements in the case where long thermocouple leads have significant resistance. in this circuit, the ptvs30vp1up transient voltage suppressor ( tvs ) quickly clamps any transient voltages to 30 v with only 1 na typical leakage current at 25 c . a 30 v tvs was chosen to allow for a 30 v dc overvoltage . a 1.69 k resistor followed by low leakage bav199lt1g schottky d iodes are used to clamp the voltage to the 5 v power rail during transient and dc overvoltage events. the 1.69 k resistor limits t he current through the external diodes to about 15 ma during a 30 v dc overvoltage condition. in order to ensure the power rail is able to sink this current , a zener diode is used to clamp the power rail to ensure it does not exceed the absolute maximum ra ting of any of the ics connected to the supply. the 5. 6 v zener diode (nzh5v6b) is selected for this purpose. a 300 resistor limits any further current that could flow into the ad 7193 or the adg738 . isolation the adum5401 and the adum1280 use adi i coupler? technology provide 2500 v rms isolation voltage between the measurement side and the controller side of the circuit . the adum5401 also provides the isolated power for measurement side of the circuit . the iso power technique used in the adum5401 uses high frequency switching elements to transfer power through a transformer. special care must be taken with the printed circuit board (pcb) layout to meet emissions standards. refer to an - 0971 application note for board layout recommendations. thermocouple conf iguration test results the performance of the circuit is highly depend ent on the sensor and the configuration of the ad 7193. the t ype - k thermocouple output varies from ? 10 mv to + 60 mv , corresponding to ?200c to +1350c. th e ad 7193 pga is configured for g = 32 . the voltage swing out of the pga is ? 320 mv to + 1.92 v , or 2.24 v p - p. with chop enable d , 50 hz / 60hz noise reduction enable d , and filter word fs[9:0] = 96, the noise distribution histogram for 1024 samples is shown in figure 6 . figure 6. noise d istribution h istogram of cn - 0287 (vdd = 5 v, vref = 4.096 v, d ifferential i nput , b i polar, i nput b uffer e nable , o utput d ata rate = 50 hz, gain = 32, c hop e nable, 60 hz r ejection e nable , s inc 4 ) the resolution of the ad 7193 is 24 bits , or 2 24 = 16,777,216 codes. the full dynamic range of the ad 7193 is 2 v ref = 2 4.096 v = 8.192 v. the output voltage of the thermocouple after the pga is only 2.24 v p - p and does not occupy all the dyna mic range of the ad 7193. therefore the range of the system is decreased by a factor of 2.24 v/8.192v . the noise distribution is about 40 codes peak - to - pea k . t he noise - free code resolution over the 2.24 vp - p range of measurement is given by: bits 8 . 16 v 192 . 8 v 24 . 2 400 216 , 777 , 16 log 2 = ? ? ? ? ? ? ? ? = resolution free noise (6) the full - scale temperature range of the type - k thermocouple is ?200c to +1350c, or 1550c p - p. the 16.8 bits of noise - free code resolution therefore corresponds to 0.013 c of noise - free temperature resolution. +5v n tvs 30v, 600w ptvs30vp1up overvoltage up to 30v schottk diodes bav199lt1g +5v 15ma +6v, 9 adc input +5.3v, 9 3ma 5.6v zener diode nzh5v6b 10926-005 1 10 100 90 80 70 60 number of occurences number of occurences 50 40 30 20 10 8388510 8388515 8388520 8388525 8388530 8388535 8388540 8388545 8388550 0 10926-006
cn- 0287 circuit note rev. c | page 6 of 9 thermocouple measurement linearity figure 7 shows the approximate linearity of the type k therm ocouple system . t he cold junction temperature is 0c in this plot . figure 7. type k t hermocouple t emperature vs . o utput v oltage with 0 c c old - j unction the precision voltage for calibration as well as testing is provided by the f luke 5700a c alibrator high precision dc voltage source with a resolution of 10 n v. t h e voltage error in f igure 8 is within 0.2 v of ideal, corresponding to about 0.004 c . this result is the short time accuracy result just after a system calibration a t 25 c without the effects of temperature drift .t he dominant error for this circuit is from the cold - junction compensation measurement. in this circuit the adt7310 is used for cold - junction compensation and has a typical error of ? 0.05c, and a worst case error of 0.8c over the ? 40c to + 105c temperature range for a 5 v supply . t he device has a 0.4c maximum error over this temperature range if a 3 v supply is used. figure 8. error of cn - 0287 c onfigured for type k thermocouple (vdd = 5 v, v ref = 4.096 v, differential input, b i polar, input buffer enable, output data rate = 50 hz, gain = 32, chop enable. 60 hz rejection enable, sinc 4 ) rtd configuration test results for a pt100 rtd, the default adc gain setting is g = 8, and for a pt1000 rtd the default gain setting is g = 1. the reference voltage to the adc is equal to the voltage across the 4.02 k? reference resistor. the temperature coefficient of a pt100 rtd is approximately 0.385 ?/c, and at +850c the resistance can be as high as 400 ?. with a 400 a default excitation current, the maximum rtd voltage is therefo re about 160 mv. the reference voltage to the adc is 4.02 k? 400 a = 1.608 v. for g = 8, the maximum rtd voltage is 160 mv 8 = 1.28 v which is approximately 80% of the available range. for a pt1000 rtd , the maximum resistance at +850c is approximate ly 4000 ?. the default excitation current is 380 a, yielding a maximum rtd voltage of 1.52 v. the reference voltage to the adc is 4.02 k? 380 a = 1.53 v. a default gain setting of g = 1 is used , and the maximum rtd voltage utilizes nearly all of the av ailable range . the general expression for the rtd resistance, r, in terms of the adc code (code), resolution (n), reference resistor (r ref ), and gain (g) is given by: ? ? ? ? ? ? ? ? = g r code r ref n 2 (7) the leakage current from tvs, diodes, clamping diodes, and ad c are the largest sources of errors in the rtd measurement circuit , even though nanoamp devices were selected for the design. the total leakage current for each of the inputs is 9 na (3 na from ad 7193, b uffer o n), 5 na from clamping diode and 1 na from the tvs diode). all four channels will thus generate 36 na max imum leakage current . the feedback loop in figure 2 maintains a constant current through the reference resistor. this means that leakage currents affect the rtd excitation current , thereby producing an error . the default exciting current is 400 a for p t 100 and 380 a for p t 1000. the approximate worst case system error due to the leakage current s for pt100 rtds is : reading of error(%) % 01 . 0 100 a ? ? ? ? ? ? ? ? = (8) for a p t 100 with measurable range from ? 200c to + 850c, this corresponds to a system accuracy of approximately ? ? ? ? ? = ) c accuracy (9) the amount of the error depends on the configuration of the input terminals. after a n input configuration is established, a room temperature calibration can reduce the erro r even further. an experiment was conducted to show the effects of leakage current. each channel was first configured as a 4 - w rtd. a 100 ? fixed resistor was connected to channel 1 in the rtd position. zero ohm resistor s were connected to the inputs of t he other three channels. 60 50 C500 0 500 temper a ture (c) volt age (mv) 1000 1500 40 30 20 10 0 C10 10926-007 0.20 0.15 0.05 1 6 1 1 16 21 26 31 36 41 46 51 input vo lt age (mv) volt age error (v) 0.10 0 10926-008
circuit note cn- 0287 rev. c | page 7 of 9 the gain was set for g = 1, and the excitation current for 380 a (pt1000 configuration). data was collected, then the jumpers connecting channel 4, channel 3, and channel 2 were removed sequentially, and data collected for each c ondition. the results are shown in figure 9 . figure 9. e rror g enerated by l eakage c urrent on channel 1 for 4 - c hannel pt100 rtd with g = 1 the adc code changed from approximately 437,800 to 437,600 corresponding to a measurement change of 104.9015 ? to 104.8627 , or 0.0388 ?. this represents a measurement error of approximately 0.1c ; however it can be removed by calibrating at room temperatur e with a fixed input configuration. c ommon variations the ad779x l ow n oise, l ow p ower, 16 - /24 - b it sigma - delta adc family is more suitable for single channel or low power applications. the adt7311 , 0.5c a ccurate, 16 - b it d igital spi t emperature s ensor is q ualified for automotive applications . the cold junction compensation circuit accuracy can be improved by using a digital temperature sensor, such as adt7320 , with 0.25 c accuracy. rms isolation up to 5 k v is be available in the adum6401 digital isolato r with dc - to - dc converter . circuit evaluation a nd test this circuit uses the e va l - cn0287 - sdpz circuit board and the sdp - b ( e va l - sdp - cb1z ) s ystem d emonstration p latform controller board. the two boards have 120 - pin mating connectors, allowing for t he quick setup and evaluation of the performance of the circuit. the e va l - cn0287 - sdpz board contains the circuit to be evaluated, a s described in this note, and the sdp - b controller board is used with the cn - 0287 evaluation software to capture the data from the e va l - cn0287 - sdpz circuit board . equipment needed the following equipment is needed: ? a pc with a usb port and windows? xp (32 bit), windows vista?, or windows? 7 ? the e va l - cn0287 - sdpz circuit board ? the e va l - sdp - cb1z sdp - b controller board ? the cn - 0287 sdp evaluation software ? the e va l - cftl - 6v - pwrz dc power supply or equ ivalent 6 v/1 a bench supply ? a rtd or thermocouple sensor o r sensor simulator. (the evaluation software supports the following rtd s: p t 100, p t 1000; thermocouple: type k, type j, type t, type s.) getting started install the evaluation software by placing the cn - 0287 evaluation software into the cd drive of the pc. using my computer, locate the drive that contains the evaluation software. functional bloc k diagram see f igure 1 for the circuit block diagram and the eval - cn02 87 - sdpz - padsschematic.pdf file for the complete circuit schematic. this file is contained in the cn02 87 design support package located at www.analog.com/cn0287 - designsupport a functional block diagram of the test setup is shown in figure 10. figure 10 . test setup functional block diagram setup connect the 120 - pin connector on the e va l - cn0287 - sdpz circuit board to the con a connector on the e va l - sdp - cb1z controller board (sdp - b). use nylon hardware to firmly secure the two boards, using the holes provided at the ends of the 120 - pin connectors. with power to the supply off, connect a 6 v power sup ply to the +6 v and gnd pins on the board. if available, a 6 v wall wart can be connected to the barrel connector j2 on the board and used in place of the 6 v power supply. connect the usb cable supplied with the sdp - b board to the usb port on the pc. do n ot connect the usb cable to the mini - usb connector on the sdp - b board at this time. turn on the 6 v power supply to power up the evaluation board and sdp board, then plug in the mini - usb cable into the mini - usb port on the sdp board. 437860 437840 437760 437820 437780 437800 437740 437720 437700 437680 437660 437640 437620 437600 437580 10926-009 al l leakage included leakage from ch4 removed leakage from ch3 removed leakage from ch2 removed sensors e v al-cftl-6 v -pwrz 6v w al l w art cn(x) jp(x) (x) = 1, 2, 3, 4 e v al-cn0287-sdpz board cn5 or j2 120 pins usb cable usb e v al-sdp-cb1z sd p board pc sd p connec t or or signa l gener a t ors 1.000v 10926-010
cn- 0287 circuit note rev. c | page 8 of 9 test launch the eval uation software . after usb communications are established, the sdp - b board can be used to send, receive, and capture data from the e va l - cn0287 - sdpz board. figure 11 shows a photo of the e va l - cn0287 - sdpz evaluation board connected to the sdp board. information regarding the sdp - b board can be found in the sdp - b user guide . information and details regarding test setup and calibration, and how to use the evaluation software for data capture can be found in the cn - 0287 software user guide . connectivity for pr ototype development the e va l - cn0287 - sdpz evaluation board is designed to use the e va l - sdp - cb1z sdp - b board; however, any microprocessor can be used to interface to the spi interface through the pmod connector j6 . the pin definition of pmod connector can be found in th e schematics of cn0287 evaluation board in cn - 0287 design support package . in order for another controller to be used with the e va l - cn0287 - sdpz evaluation board, software must be developed by a third party. figure 11 . eval - cn0287 - sdpz evaluation board connected to the eval - sdp - cb1z sdp - b board 10926-0 1 1
cn- 0287 circuit note rev. c | page 9 of 9 l earn m ore cn - 0287 design support package: www.analog.com/cn0287 - designsupport sdp - b user guide an - 880 application note, adc requirements for temperature measurement , analog devices. an - 892 application note, temperature measurement theory and practical techniques , analog devices . an - 0970 application note, rtd interfacing and linearization using an aduc706x microcontroller , analog devices. cn - 0172, high accuracy multichannel t hermocouple measurement solution , analog devices . cn - 0206, complete type t thermocouple measurement system with cold junction compensation , analog devices . cn - 0209, fully programmable universal analog front end for process control applications , analog devices . cn - 0221, usb - based temperature monitor using th e aducm360 precision analog microcontroller and an external thermocouple , analog devices . cn - 0271, k - type thermocouple measurement system with integrated cold junction compensation , analog device s. kester, walt. 1999. sensor signal conditioning. analog devices. chapter 7, "temperature sensors." matthew duff and joseph towey. two ways to measure temperature using thermocouples feature simplicity, accuracy, and flexibility , analog dialogue 44 - 10, analog devices . mary mccarthy , an - 615 appl ication note , peak - to - peak resolution versus effective resolution . mt - 049 tutorial, op amp total output noise calculations for single - pole system . analog devices. mt - 004 tutorial, the good, the bad, and the ugly aspects of adc input noise is no noise good noise? analog devices. mt - 031 tutorial, grounding data converters and solving the mystery of agnd and dgnd , analog devices. mt - 035, op amp inputs, outputs, single - supply, and rail - to - rail issues , analog devices . mt - 101 tutorial, decoupling te chni ques , analog devices . data sheets and evaluation boards cn - 0287 circuit evaluation board (eval - cn02 87 - sdpz ) system demonstration platform (eval - sdp - cb1z) ad7193 datasheet ad8603 datasheet adg738 datasheet adg702 datasheet adt7310 datasheet adum5 4 01 datasheet adum1280 datasheet AD5201 datasheet adr3440 datasheet revision history 2 /14 rev. b to rev. c change to common variations section ........................................ 7 9/13 rev. a to rev. b changes to figure 1 .......................................................................... 1 8/13 rev. 0 to rev. a changes to title ................................................................................. 1 8 /1 3 rev ision 0 : initial version (continued from first page) circuits from the lab reference designs are intended only for use with analog devices products and are the intellectual property of analog devices or its licensors. while you may use the circuits from the lab reference designs in the design of your product, no other license is granted by implic ation or otherwise under any patents or other intellectual property by application or use of the circuits from the lab reference designs . information furnished by analog devices is believed to be accurate and reliable. however, circuits from the lab refere nce designs are supplied "as is" and without warranties of any kind, express, implied, or statutory including, but not limited to, any im plied warranty of merchantability, noninfringement or fitness for a particular purpose and no responsibility is assumed by analog devices for their use, nor for any infringements of patents or other rights of third parties that may result from their use. analog devices reserves the right to change any circuits from the lab reference designs at any time without notice but i s under no obligation to do so. ? 2013 C 2014 analog devices, inc. all rights reserved. trademarks and registered trademarks are the property of their respective owners. cn10926 - 0 - 2/14(c)
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