ADT7302 AD | Alldatasheet
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±2°C Accurate, MicroPower Digital Temperature Sensor in 6-Lead SOT-23 Preliminary Technical Data ADT7302 Rev. PrE 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. Specifications subject to change without notice. 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. Tel: 781.329.4700 www.analog.com Fax: 781.326.8703 © 2004 Analog Devices, Inc. All rights reserved.
FEATURES
13-bit temperature-to-digital converter −40°C to +125°C operating temperature range ±2°C accuracy 0.03125°C temperature resolution Shutdown current of 1 µA Power dissipation of 0.631 mW at V DD = 3.3 V SPI- and DSP-compatible serial interface Shutdown mode Space-saving SOT-23 and MSOP packages
APPLICATIONS
Automotive: Environmental controls Oil temperature Hydraulic systems Cell phones Hard disk drives Personal computers Electronic test equipment Office equipment Domestic appliances Process control FUNCTIONAL BLOCK DIAGRAM SERIAL BUS INTERFACE 04662-C-001 ADT7302 VDD SCLK DIN DOUT GND 13-BIT ANALOG/DIGITAL CONVERTER TEMPERATURE VALUE REGISTER BAND GAP TEMPERATURE SENSOR CS Figure 1. Functional Block Diagram the temperature reading to a resolution of 0.03125°C. automotive, and domestic appliances.
- The ADT7302 has an on-chip temperature sensor that
- Supply voltage of 2.7 V to 5.5 V .
- Space-saving 6-lead SOT-23 and 8-lead MSOP packages.
- Temperature accuracy of ±2°C.
- 13-bit temperature reading to 0.03125°C resolution.
- The ADT7302 features a shutdown mode that reduces the
ADT7302 Preliminary Technical Data Rev. PrE | Page 2 of 14 TABLE OF CONTENTS
REVISION HISTORY
Revision PrE: Preliminary V ersion
Preliminary Technical Data ADT7302 Rev. PrE | Page 3 of 14 SPECIFICATIONS TA = TMIN to TMAX, VDD = 2.7 V to 5.5 V , unless otherwise noted. All specifications apply for –40°C to +125°C, unless otherwise stated Table 1. Parameter Min Typ Max Unit Test Conditions/Comments TEMPERATURE SENSOR AND ADC V DD = +3.3 V (±10%) and 5 V (±10%) Accuracy TBD ±2 °C T A = 0°C to 70°C. TBD ±2.5 °C T A = −20°C to +85°C. TBD ±3 °C T A = −40°C to +125°C. Temperature Resolution 0.03125 °C Auto Conversion Update Rate, tR 1 sec Temperature measurement every 1 second Temperature Conversion Time 2 ms Thermal Time Constant1 2 sec SUPPLIES Supply Voltage 2.7 5.5 V For Specified performance. Supply Current Normal Mode 1.6 2.2 mA V DD = 3.3 V. Powered up and converting 190 300 µA V DD = 3.3 V. Powered up and not converting 1.6 2.2 mA V DD = 5 V. Powered up and converting 280 400 µA V DD = 5 V. Powered up and not converting Shutdown Mode 0.2 1 µA V DD = 3.3 V. 0.2 1 µA V DD = 5 V. Power Dissipation Normal Mode (Average) 631 µW V DD = 3.3 V. Auto conversion update, tR. 1.41 mW V DD = 5 V. Auto conversion update, tR. Shutdown Mode (Average)2 1 SPS 4.88 µW V DD = 3.3 V 7.4 µW V DD = 5 V 10 SPS 42.9 µW V DD = 3.3 V 65 µW V DD = 5 V 100 SPS 423 µW V DD = 3.3 V 641 µW V DD = 5 V DIGITAL INPUT3 Input High Voltage, VIH 2.5 V Input Low Voltage, VIL 0.8 V Input Current, IIN ±1 µA V IN = 0 V to VDD Input Capacitance, CIN 10 pF All digital inputs DIGITAL OUTPUT3 Output High Voltage, VOH V DD − 0.3 V I SOURCE = ISINK = 200 µA Output Low Voltage, VOL 0.4 V I OL = 200 µA Output Capacitance, COUT 50 pF 1 Thermal Time Constant is the time it takes for a starting temperature difference to change to 36.8% of it’s starting value. Fo r example if the ADT7302 experienced a thermal shock from 0°C to 100°C, it would take typically 2 secs for the ADT7302 to reach 63.2°C. 2 The ADT7302 is taken out of shutdown mode and a temperature conversion is immediately performed after this write operation. On ce the temperature conversion is complete, the ADT7302 is put back into shutdown mode. 3 Guaranteed by design and characterization, not production tested.
and timed from a voltage level of 1.6 V . See Figure 3. TA = TMIN to TMAX, VDD = 2.7 V to 5.5 V , unless otherwise noted. 1 Measured with the load circuit of Figure 2. Figure 2. Load Circuit for Data Access Time and Bus Relinquish Time
serial interface logic functions in SOT-23 and MSOP packages. register because the serial interface circuitry never shuts down. shutdown mode by writing all zeros into the control register. operation provides the previous result. +125°C). A typical performance curve is shown in Figure 6. Table 5. Temperature Data Format
- Positive Temperature = ADC Code(d)/32
- Negative Temperature = (ADC Code*(d) – 16384)/32
*Using all 14 bits of the data byte, includes the sign bit. Figure 12. Temperature to Digital Transfer Function
Preliminary Technical Data ADT7302 Rev. PrE | Page 11 of 14 #include <16F873.h> #device adc=8 #use delay(clock=4000000) #fuses NOWDT,XT, PUT, NOPROTECT, BROWNOUT, LVP #BIT CKP = 0x14.4 #define CS PIN_A1 void main(){ int MSByte,LSByte; long int ADC_Temp_Code; float TempVal,ADC_Temp_Code_dec; setup_spi(spi_master); //Pic is set up as Master device. CKP = 1; //Idle state of clock is high. do{ delay_ms(10); //Allow time for conversions. Output_low(CS); //Pull CS low. delay_us(10); //CS to SCLK setup time. MSByte = SPI_Read(0); //The first byte is clocked in. LSByte = SPI_Read(0); //The second byte is clocked in. delay_us(10); //SCLK to CS setup time. Output_High(CS); //Bring CS high. MSByte = 0x03; LSByte = 0x20; ADC_Temp_Code = make16(MSByte,LSByte); //16bit ADC code is stored ADC_Temp_Code. ADC_Temp_Code_dec = (float)ADC_Temp_Code; //Covert to float for division. if ((0x2000 & ADC_Temp_Code) == 0x2000) //Check sign bit for negative value. TempVal = (ADC_Temp_Code_dec - 16384)/32; //Conversion formula if negative temperature. else TempVal = (ADC_Temp_Code_dec/32); //Conversion formula if positive temperature. }while(True); //Temperature value stored in TempVal.
2.90 BSC
0.95 BSC
0.15 MAX
0.90 SEATING
1.45 MAX
Figure 18. 6-Lead Small Outline Transistor Package [SOT-23]
0.65 BSC
1.10 MAX
Figure 19. 8-Lead Mini Small Outline Package [MSOP]
ADT7302 Preliminary Technical Data Rev. PrE | Page 14 of 14 ORDERING GUIDE Model Temperature Range Temperature Accuracy1 Package
Description
ADT7302ART-500RL7 −40°C to +125°C ±2°C 6-Lead SOT-23 T01 RJ-6 ADT7302ART-REEL7 −40°C to +125°C ±2°C 6-Lead SOT-23 T01 RJ-6 ADT7302ART-REEL −40°C to +125°C ±2°C 6-Lead SOT-23 T01 RJ-6 ADT7302ARM −40°C to +125°C ±2°C 8-Lead MSOP RM-8 ADT7302ARM-REEL7 −40°C to +125°C ±2°C 8-Lead MSOP RM-8 ADT7302ARM-REEL −40°C to +125°C ±2°C 8-Lead MSOP RM-8 ADT7302ARTZ-500RL72 −40°C to +125°C ±2°C 6-Lead SOT-23 RJ-6 ADT7302ARTZ-REEL72 −40°C to +125°C ±2°C 6-Lead SOT-23 RJ-6 ADT7302ARTZ-REEL2 −40°C to +125°C ±2°C 6-Lead SOT-23 RJ-6 ADT7302ARMZ2 −40°C to +125°C ±2°C 8-Lead MSOP RM-8 ADT7302ARMZ-REEL72 −40°C to +125°C ±2°C 8-Lead MSOP RM-8 ADT7302ARMZ-REEL2 −40°C to +125°C ±2°C 8-Lead MSOP RM-8 1 Temperature accuracy is over 0°C to 70°C temperature range. 2 Z = Pb-free. © 2004 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners.