rev. e a ad7814 information furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. no license is granted by implication or otherwise under any patent or patent rights of analog devices. trademarks and registered trademarks are the property of their respective owners. one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 781/329-4700 www.analog.com fax: 781/326-8703 ?2004 analog devices, inc. all rights reserved. 10-bit digital temperature sensor in 6-lead sot-23 functional block diagram serial bus interface ad7814 v dd cs sclk din dout gnd temperature value register 10-bit analog/digital converter band gap temperature sensor features 10-bit temperature-to-digital converter ?5 c to +125 c operating temperature range 2 c accuracy spi- and dsp-compatible serial interface shutdown mode space-saving sot-23 package applications hard disk drives personal computers electronic test equipment office equipment domestic appliances process control general description the ad7814 is a complete temperature monitoring system in a sot-23 package or 8-lead msop package. it contains a band gap temperature sensor and 10-bit adc to monitor and digitize the temperature reading to a resolution of 0.25 c. the ad7814 has a flexible serial interface that allows easy inter- facing to most microcontrollers. the interface is compatible with spi , qspi , and microwire protocol, and is also compatible with dsps. the part features a standby mode that is controlled via the serial interface. the ad7814? wide supply voltage range, low supply current, a nd spi-compatible interface make it ideal for a variety of a pplications, including personal computers, office equipment, and domestic appliances. purchase of licensed i 2 c components of analog devices or one of its sublicensed associated companies conveys a license for the purchaser under the philips i 2 c patent rights to use these components in an i 2 c system, provided that the system conforms to the i 2 c standard specification as defined by philips. product highlights 1. the ad7814 has an on-chip temperature sensor that allows an accurate measurement of the ambient temperature. the measurable temperature range is ?5 c to +125 c, with a 2 c temperature accuracy. 2. supply voltage of 2.7 v to 5.5 v 3. space-saving 6-lead sot-23 package and 8-lead msop package 4. 10-bit temperature reading to 0.25 c resolution 5. standby mode that reduces the current consumption to 1 a
rev. e e2e ad7814especifications 1 parameter min typ max unit test conditions/comments temperature sensor and adc accuracy 2.0 ct a = 0 c to 85 c. v dd = 3 v to 5.5 v 2 2.5 ct a = e40 c to 0 c. v dd = 3 v to 5.5 v 2 2.0 3.5 ct a = e55 c to +125 c. v dd = 3 v to 5.5 v resolution 10 bits update rate, t r 400 s temperature conversion time 25 s supplies supply voltage 2.7 5.5 v for specified performance supply current normal mode 250 400 a shutdown mode (v dd = 5 v) 1.23 3 a shutdown mode (v dd = 3 v) 0.43 1 a power dissipation 80 wv dd = 3 v. using normal mode power dissipation v dd = 3 v. using shutdown mode 1 sps 3.7 w 10 sps 3.9 w 100 sps 5.8 w digital input 3 input high voltage, v ih 2.4 v input low voltage, v il 0.8 v input current, i in 1 av in = 0 v to v dd input capacitance, c in 10 pf all digital inputs digital output 3 output high voltage, v oh v dd e 0.3 v i source = i sink = 200 a output low voltage, v ol 0.4 v i ol = 200 a output capacitance, c out 50 pf notes 1 all specifications apply for e55 c to +125 c unless otherwise stated. 2 for v dd = 2.7 v to 3 v and t a = e40 c to +85 c, the typical temperature error is 2 c. 3 guaranteed by design and characterization, not production tested. specifications subject to change without notice. timing characteristics 1, 2, 3 parameter limit unit comments t 1 0 ns min cs scs sc sc sc ssc sc cs sc cs s s s
rev. e e3e ad7814 ordering guide temperature temperature package package branding model range error 1 description option information ad7814art-500rl7 e55 c to +125 c 2 c 6-lead sot-23 rt-6 caa ad7814art-reel e55 c to +125 c 2 c 6-lead sot-23 rt-6 caa ad7814art-reel7 e55 c to +125 c 2 c 6-lead sot-23 rt-6 caa ad7814artz-500rl7 2 e55 c to +125 c 2 c 6-lead sot-23 rt-6 caa AD7814ARTZ-REEL 2 e55 c to +125 c 2 c 6-lead sot-23 rt-6 caa AD7814ARTZ-REEL7 2 e55 c to +125 c 2 c 6-lead sot-23 rt-6 caa ad7814arm e55 c to +125 c 2 c 8-lead msop rm-8 caa ad7814arm-reel e55 c to +125 c 2 c 8-lead msop rm-8 caa ad7814arm-reel7 e55 c to +125 c 2 c 8-lead msop rm-8 caa ad7814armz 2 e55 c to +125 c 2 c 8-lead msop rm-8 caa ad7814armz-reel 2 e55 c to +125 c 2 c 8-lead msop rm-8 caa ad7814armz-reel7 2 e55 c to +125 c 2 c 8-lead msop rm-8 caa 1 temperature error is over 0 c to 85 c temperature range. 2 z = pb-free part absolute maximum ratings * v dd to gnd . . . . . . . . . . . . . . . . . . . . . . . . . . e0.3 v to +7 v digital input voltage to gnd . . . . . . . e0.3 v to v dd + 0.3 v digital output voltage to gnd . . . . . e0.3 v to v dd + 0.3 v operating temperature range . . . . . . . . . . e55 c to +125 c storage temperature range . . . . . . . . . . . . e65 c to +150 c junction temperature . . . . . . . . . . . . . . . . . . . . . . . . . 150 c sot-23, power dissipation . . . . . . . . . . . . . . . . . . . . 450 mw ja thermal impedance . . . . . . . . . . . . . . . . . . . . 240 c/w lead temperature, soldering vapor phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . 215 c infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . 220 c msop package, power dissipation . . . . . . . . . . . . . . 450 mw ja thermal impedance . . . . . . . . . . . . . . . . . . . . 206 c/w lead temperature, soldering vapor phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . 215 c infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . 220 c * stresses above those listed under absolute maximum ratings may cause perma- nent damage to the device. this is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. caution esd (electrostatic discharge) sensitive device. electrostatic charges as high as 4000 v readily accumulate on the human body and test equipment and can discharge without detection. although the ad7814 features proprietary esd protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. therefore, proper esd precautions are recommended to avoid performance degradation or loss of functionality. warning! esd sensitive device 1.6v i ol 200 a 200 a i oh to output pin c l 50pf figure 1. load circuit for data access time and bus relinquish time
rev. e ad7814 e4e pin function descriptions pin sot-23 msop mnemonic pin no. pin no. description gnd 1 7 analog and digital ground din 2 6 serial data input. serial data to be loaded to the part?s control register is provided on this input. data is clocked into the control register on the rising edge of sclk. v dd 35 positive supply voltage, 2.7 v to 5.5 v sclk 4 4 serial clock input. this is the clock input for the serial port. the serial clock is used to clock data out of the temperature value register of the ad7814 and to clock data into the control register on the part. cs cs sc s sc c c cs s s cs sc s s ccc c cs sc c
rev. e e5e ad7814 circuit information the ad7814 is a 10-bit digital temperature sensor. the part houses an on-chip temperature sensor, a 10-bit a/d converter, a reference, and serial interface logic functions in a sot-23 package. the a/d converter section consists of a conventional successive-approximation co nverter based around a capacitor d ac. the parts are capable of running on a 2.7 v to 5.5 v power supply. the on-chip temperature sensor allows an accurate measurement of the ambi ent device tem perature to be made. the working measurement range of the ad7814 is e55 c to +125 c. converter details the conversion clock for the part is internally generated so no external clock is required except when reading from and writing to the serial port. in normal mode, an internal clock oscillator runs the automatic conversion sequence. a conversion is initi- ated approximately every 350 s. at this time, the part wakes up and performs a temperature conversion. this temperature con- version typically takes 25 s, at which time the part automati- cally shuts down. the result of the most recent temperature conversion is available in the serial output register at any time. once the conversion is finished, an internal oscillator starts counting and is designed to time out every 350 s. the ad7814 then powers up and does a conversion. please note that if the cs is brought low every 350 s ( 30%), then the same tempera- ture value will be output onto the dout line every time with- out changing. it is recommended that the cs cs cs cs s s c c c c c c c c c c c c c c c c c c c c c c sc cs sc cs sc c ccccc s
rev. e ad7814 e6e read operation figure 2 shows the timing diagram for a serial read from the ad7814. the cs sc cs sc sc cs sc ccssc cs sc sc cs s cs sc c c s cc cccc c ccc sc ccc cs sc cs cc sc s s c sc cc c c s cs c cs sc cs
rev. e e7e ad7814 ad7814 * sclk dout din cs 8051 * p3.1 p3.0 p1.2 p1.3 * additional pins omitted for clarity figure 4. ad7814 to 8051 interface ad7814 to pic16c6x/7x interface figure 5 shows an interface circuit between the ad7814 and the pic16c6x/7x microcontroller. the pic16c6x/7x synchronous serial port (ssp) is configured as an spi master with the clock polarity bit set to a logic one. in this mode, the serial clock line of the pic16c6x/7x idles high between data transfers. data is transferred to and from the ad7814 in two 8-bit serial data operations. in the example shown, port line ra1 is being used to generate the cs sc cs cc sc s s sc cc s ss s ss sss s scsc ss ssc ssc sc sscs sss sss s sc cs s sc s sc s s c c c c sc c
rev. e ad7814 e8e c01041e0e8/04(e) outline dimensions 6-lead small outline transistor package [sot-23] (rt-6) dimensions shown in millimeters 1 3 4 5 2 6 2.90 bsc 1.60 bsc 2.80 bsc 1.90 bsc 0.95 bsc 0.22 0.08 10 4 0 0.50 0.30 0.15 max 1.30 1.15 0.90 seating plane 1.45 max 0.60 0.45 0.30 pin 1 indicator compliant to jedec standards mo-178ab 8-lead mini small outline package [msop] (rm-8) dimensions shown in millimeters 0.80 0.60 0.40 8 0 85 4 1 4.90 bsc pin 1 0.65 bsc 3.00 bsc seating plane 0.15 0.00 0.38 0.22 1.10 max 3.00 bsc coplanarity 0.10 0.23 0.08 compliant to jedec standards mo-187aa revision history location page 8/04?data sheet changed from rev. d to rev. e. changes to ordering guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 changes to converter details section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 changes to read operation section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 updated outline dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5/02?data sheet changed from rev. c to rev. d. updates to specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
|
