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±0.25°C Accurate, 16-Bit Digital SPI Temperature Sensor Data Sheet ADT7320 Rev. 0 Document Feedback 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 © 2012 Analog Devices, Inc. All rights reserved. Technical Support www.analog.com
FEATURES
±0.20°C from −10°C to +85°C at 3.0 V ±0.25°C from −20°C to +105°C at 2.7 V to 3.3 V 16-bit temperature resolution: 0.0078°C Ultralow temperature drift: 0.0073°C NIST traceable or equivalent Fast first temperature conversion on power-up of 6 ms Easy implementation No temperature calibration/correction required by user No linearity correction required Low power Power saving 1 sample per second (SPS) mode 700 µW typical at 3.3 V in normal mode 7 µW typical at 3.3 V in shutdown mode Wide operating ranges Temperature range: −40°C to +150°C Voltage range: 2.7 V to 5.5 V Programmable interrupts Critical overtemperature interrupt Overtemperature/undertemperature interrupt SPI-compatible interface 16-lead, RoHS-compliant, 4 mm × 4 mm LFCSP package
APPLICATIONS
RTD and thermistor replacement Thermocouple cold junction compensation Medical equipment Industrial control and test Food transportation and storage Environmental monitoring and HVAC Laser diode temperature control GENERAL DESCRIPTION The ADT7320 is a high accuracy digital temperature sensor that offers breakthrough performance over a wide industrial temperature range, housed in a 4 mm × 4 mm LFCSP package. It contains an internal band gap reference, a temperature sensor, and a 16-bit analog-to-digital converter (ADC) to monitor and digitize the temperature to a resolution of 0.0078°C. The ADC resolution, by default, is set to 13 bits (0.0625°C). The ADC resolution is a user programmable mode that can be changed through the serial interface. The ADT7320 is guaranteed to operate over supply voltages from 2.7 V to 5.5 V . Operating at 3.3 V , the average supply current is typically 210 µA. The ADT7320 has a shutdown mode that powers down the device and offers a shutdown current of typically 2.0 µA at 3.3 V. The ADT7320 is rated for operation over the −40°C to +150°C temperature range. The CT pin is an open-drain output that becomes active when the temperature exceeds a programmable critical temperature limit. The INT pin is also an open-drain output that becomes active when the temperature exceeds a programmable limit. The INT pin and CT pin can operate in either comparator or interrupt mode. PRODUCT HIGHLIGHTS 1. Ease of use, no calibration or correction required by the user. 2. Low power consumption. 3. Excellent long term stability and reliability. 4. High accuracy for industrial, instrumentation, and medical applications. 5. Packaged in a 16-lead, RoHS-compliant, 4 mm × 4 mm LFCSP package. FUNCTIONAL BLOCK DIAGRAM INTERNAL REFERENCE TEMPERATURE SENSOR THIGH TCRIT TLOW INTERNAL OSCILLATOR FILTER LOGIC Σ-Δ MODULATOR VDD GND CT INT ADT7320TEMPERATURE VALUE REGISTER CONFIGURATION REGISTER THYST REGISTER TLOW REGISTER THIGH REGISTER TCRIT REGISTER ID REGISTER STATUS REGISTER SCLK DOUT DIN CS SPI INTERFACE 09012-001 Figure 1.
Rev. 0 | Page 2 of 24 TABLE OF CONTENTS
REVISION HISTORY
12/12—Revision 0: Initial Version
Rev. 0 | Page 3 of 24 SPECIFICATIONS TA = −40°C to +125°C, VDD = 2.7 V to 5.5 V, unless otherwise noted. Table 1. Parameter Min Typ Max Unit Test Conditions/Comments TEMPERATURE SENSOR AND ADC Accuracy1 0.0017 ±0.202 °C TA = −10°C to +85°C, VDD = 3.0 V ±0.25 °C TA = −20°C to +105°C, VDD = 2.7 V to 3.3 V ±0.31 °C TA = −40°C to +105°C, VDD = 3.0 V ±0.35 °C TA = −40°C to +105°C, VDD = 2.7 V to 3.3 V ±0.50 °C TA = −40°C to +125°C, VDD = 2.7 V to 3.3 V ±0.503 °C TA = −10°C to +105°C, VDD = 4.5 V to 5.5 V ±0.66 °C TA = −40°C to +125°C, VDD = 4.5 V to 5.5 V −0.85 °C TA = +150°C, VDD = 4.5 V to 5.5 V −1.0 °C TA = +150°C, VDD = 2.7 V to 3.3 V ADC Resolution 13 Bits Twos complement temperature value of sign bit plus
12 ADC bits (power-up default resolution)
16 Bits Twos complement temperature value of sign bit plus
15 ADC bits (Bit 7 = 1 in the configuration register)
13-Bit 0.0625 °C 13-bit resolution (sign + 12 bits) 16-Bit 0.0078 °C 16-bit resolution (sign + 15 bits) Temperature Conversion Time 240 ms Continuous conversion and one-shot conversion mode Fast Temperature Conversion Time 6 ms First conversion on power-up only
1 SPS Conversion Time 60 ms Conversion time for 1 SPS mode
Temperature Hysteresis4 ±0.002 °C Temperature cycle = 25°C to 125°C and back to 25°C Repeatability5 ±0.015 °C TA = 25°C Drift6 0.0073 °C 500 hour stress test at 150°C with VDD = 5.0 V DC PSRR 0.1 °C/V TA = 25°C DIGITAL OUTPUTS (C T, INT), OPEN DRAIN High Output Leakage Current, IOH 0.1 5 µA CT and INT pins pulled up to 5.5 V Output Low Voltage, VOL 0.4 V IOL = 3 mA at 5.5 V, IOL = 1 mA at 3.3 V Output High Voltage, VOH 0.7 × VDD V Output Capacitance, COUT 2 pF DIGITAL INPUTS (DIN, SCLK, CS) Input Current ±1 µA VIN = 0 V to VDD Input Low Voltage, VIL 0.4 V Input High Voltage, VIH 0.7 × VDD V Pin Capacitance 5 10 pF DIGITAL OUTPUT (DOUT) Output High Voltage, VOH VDD − 0.3 V ISOURCE = ISINK = 200 µA Output Low Voltage, VOL 0.4 V IOL = 200 µA Output Capacitance, COUT 50 pF POWER REQUIREMENTS Supply Voltage 2.7 5.5 V Supply Current Peak current while converting, SPI interface inactive At 3.3 V 210 265 µA At 5.5 V 250 300 µA
1 SPS Current 1 SPS mode, TA = 25°C
At 3.3 V 46 µA VDD = 3.3 V At 5.5 V 65 µA VDD = 5.5 V
1 Accuracy specification includes repeatability. 2 The equivalent 3 σ limits are ±0.15°C. This 3 σ specification is provided to enable comparison with other vendors who use these limits. 3 For higher accuracy at 5 V operation, contact Analog Devices, Inc. 4 Temperature hysteresis does not include repeatability. 5 Based on a floating average of 10 readings. 6 Drift includes solder heat resistance and lifetime test performed as per JEDEC Standard JESD22-A108. (10% to 90% of VDD) and timed from a voltage level of 1.6 V . 1 Sample tested during initial release to ensure compliance. Figure 2. Detailed SPI Timing Diagram
Rev. 0 | Page 5 of 24 ABSOLUTE MAXIMUM RATINGS Table 3. Parameter Rating VDD to GND −0.3 V to +7 V DIN Input Voltage to GND −0.3 V to VDD + 0.3 V DOUT Voltage to GND −0.3 V to VDD + 0.3 V SCLK Input Voltage to GND −0.3 V to VDD + 0.3 V CS Input Voltage to GND −0.3 V to VDD + 0.3 V CT and INT Output Voltage to GND −0.3 V to VDD + 0.3 V ESD Rating (Human Body Model) 2.0 kV Operating Temperature Range1 −40°C to +150°C Storage Temperature Range −65°C to +160°C Maximum Junction Temperature, TJMAX 150°C Power Dissipation2 16-Lead LFCSP3 W MAX = (TJMAX − TA)/θJA Thermal Impedance4 θJA, Junction-to-Ambient (Still Air) 37°C/W θJC, Junction-to-Case 33°C/W IR Reflow Soldering 220°C Peak Temperature (RoHS-Compliant Package) 260°C (0°C/−5°C) Time at Peak Temperature 20 sec to 40 sec Ramp-Up Rate 3°C/sec maximum Ramp-Down Rate −6°C/sec maximum Time from 25°C to Peak Temperature 8 minutes maximum 1 Sustained operation above 125°C results in a shorter product lifetime. For more information, contact an Analog Devices, Inc., sales representative. 2 Values relate to package being used on a standard 2-layer PCB. This gives a worst-case θJA and θJC. 3 TA = ambient temperature.
4 Junction-to-case resistance is applicable to components featuring a
preferential flow direction, for example, components mounted on a heat sink. Junction-to-ambient resistance is more useful for air cooled, PCB- mounted components. Stresses above those listed under Absolute Maximum Ratings may cause permanent 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. ESD CAUTION
17 EPAD
9 INT
- NC = NO CONNECT. DO NOT CONNECT TO THIS PIN.
THE NC PIN IS NOT BONDED TO THE DIE INTERNALLY.
- TO ENSURE CORRECT OPERATION, THE EXPOSED PAD
Figure 3. Pin Configuration Table 4. Pin Function Descriptions 1 SCLK Serial Clock Input. The serial clock is used to clock data into and out of any register of the ADT7320. 2 DOUT Serial Data Output. Data is clocked out on the SCLK falling edge and is valid on the SCLK rising edge. clocked into the registers on the rising edge of SCLK. 4 CS Chip Select Input. The device is enabled when this input is low. The device is disabled when this pin is high. 5 NC No Connect. Do not connect to this pin. The NC pin is not bonded to the die internally. 6 NC No Connect. Do not connect to this pin. The NC pin is not bonded to the die internally. 7 NC No Connect. Do not connect to this pin. The NC pin is not bonded to the die internally. 8 NC No Connect. Do not connect to this pin. The NC pin is not bonded to the die internally. comparator interrupt. Open-drain configuration. A pull-up resistor is required, typically 10 kΩ. configuration. A pull-up resistor is required, typically 10 kΩ. 11 GND Analog and Digital Ground. 13 NC No Connect. Do not connect to this pin. The NC pin is not bonded to the die internally. 14 NC No Connect. Do not connect to this pin. The NC pin is not bonded to the die internally. 15 NC No Connect. Do not connect to this pin. The NC pin is not bonded to the die internally. 16 NC No Connect. Do not connect to this pin. The NC pin is not bonded to the die internally. 17 EPAD Exposed Pad. To ensure correct operation, the exposed pad should either be left floating or connected to ground.
Figure 10. Thermal Response Time
precision digital modulator. correction or calibration by the user. deliver 16 bits of resolution in an extremely compact circuit. performance and increasing accuracy. circuit technique that results in SPI temperature data. Figure 11. Σ-∆ Modulator 1 SPS mode, and shutdown mode. read operation provides the most recent converted result.
Rev. 0 | Page 11 of 24
1 SPS MODE
In 1 SPS mode, the part performs one measurement per second. A conversion takes 60 ms typically, and the part remains in the idle state for the remaining 940 ms period. This mode is enabled by setting Bits[6:5] of the configuration register (Register Address 0x01) to 10. SHUTDOWN MODE The ADT7320 can be placed in shutdown mode by setting Bits[6:5] of the configuration register (Register Address 0x01) to 11. The ADT7320 can be taken out of shutdown mode by setting Bits[6:5] of the configuration register (Register Address 0x01) to 00. The ADT7320 typically takes 1 ms (with a 0.1 μF decoupling capacitor) to come out of shut-down mode. The conversion result from the last conversion prior to shutdown can still be read from the ADT7320 even when it is in shutdown mode. When the part is taken out of shutdown mode, the internal clock restarts and a conversion is initiated. FAULT QUEUE Bit 0 and Bit 1 of the configuration register (Register Address 0x01) are used to set up a fault queue. Up to four faults are provided to prevent false tripping of the INT and CT pins when the ADT7320 is used in a noisy temperature environment. The number of faults set in the queue must occur consecutively to set the INT and CT outputs. For example, if the number of faults set in the queue is four, then four consecutive temperature conversions must occur, with each result exceeding a temperature limit set in any of the limit registers, before the INT and CT pins are activated. If two consecutive temperature conversions exceed a temperature limit and the third conversion does not, the fault count is reset to zero.
with the low temperature limit stored in the TLOW setpoint register. the 13-bit temperature data format without Bit 0 to Bit 2. setting has a 13-bit temperature data value. Table 5. 13-Bit Temperature Data Format where the MSB is removed from the ADC code. where the MSB is removed from the ADC code. where the MSB is removed from the ADC Code. where the MSB is removed from the ADC Code.
- A status register
- A configuration register
- Five temperature registers
- An ID register The status register, temperature value register, and the ID register are read only.
Table 6. ADT7320 Registers operation mode bits in the configuration register. Table 7. Status Register (Register Address 0x00) [3:0] 0000 R Unused Reads back 0. in the TLOW + THYST setpoint registers. set in the THIGH − THYST setpoint registers. in the TCRIT − THYST setpoint registers. this bit is reset after a write to the operation mode bits in the configuration register.
overtemperature fault queues. Table 8. Configuration Register (Register Address 0x01) [2] 0 R/W CT pin polarity This bit selects the output polarity of the CT pin. [3] 0 R/W INT pin polarity This bit selects the output polarity of the INT pin. [4] 0 R/W INT/CT mode This bit selects comparator mode or interrupt mode. [6:5] 00 R/W Operation mode These two bits set the operational mode of the ADT7320. 01 = one-shot mode. Conversion time is typically 240 ms. average current consumption. 11 = shutdown. All circuitry except for the interface circuitry is powered down. [7] 0 R/W Resolution This bit sets the resolution of the ADC when converting. 0 = 13-bit resolution. Sign bit + 12 bits gives a temperature resolution of 0.0625°C. 1 = 16-bit resolution. Sign bit + 15 bits gives a temperature resolution of 0.0078°C.
Bit 2 to Bit 0. The default setting for the ID register is 0xC3. being the temperature sign bit. Table 9. Temperature Value Register (Register Address 0x02) (13-bit resolution). When the temperature value is below TLOW, this bit is set to 1. configuration register, Register Address 0x01[7] = 1 (16-bit resolution). (13-bit resolution). When the temperature value is above THIGH, this bit is set to 1. configuration register, Register Address 0x01[7] = 1 (16-bit resolution). (13-bit resolution). When the temperature value exceeds TCRIT, this bit is set to 1. configuration register, Register Address 0x01[7] = 1 (16-bit resolution). [7:3] 00000 R Temp Temperature value in twos complement format. [14:8] 0000000 R Temp Temperature value in twos complement format. 15 0 R Sign Sign bit; indicates if the temperature value is negative or positive. Table 10. ID Register (Register Address 0x03) [2:0] 011 R Revision ID Contains the silicon revision identification number. [7:3] 11000 R Manufacturer ID Contains the manufacturer identification number. Table 11. TCRIT Setpoint Register (Register Address 0x04) [15:0] 0x4980 R/W TCRIT 16-bit critical overtemperature limit, stored in twos complement format.
TLOW value to implement hysteresis. The default setting for the THYST setpoint is 5°C. bit being the temperature sign bit. being the temperature sign bit. Table 12. T [3:0] 0101 R/W THYST Hysteresis value, from 0°C to 15°C. Stored in straight binary format. The default setting is 5°C. [7:4] 0000 R/W N/A N/A = not applicable. Not used. Table 13. THIGH Setpoint Register (Register Address 0x06) [15:0] 0x2000 R/W THIGH 16-bit overtemperature limit, stored in twos complement format. Table 14. TLOW Setpoint Register (Register Address 0x07) [15:0] 0x0500 R/W TLOW 16-bit undertemperature limit, stored in twos complement format.
Figure 14. Typical SPI Interface Connection interface. CS is required for correct operation of the interface. and data is clocked into the device on the rising edge of SCLK. data transfer. shows the command byte. Table 15. Command Byte
0 R/W Register address 0 0 0
does not work correctly if a 1 is written into any of these bits. be read from or written to per bus transaction.
Figure 20. INT Output Temperature Response for TLOW Undertemperature Events
COMPLIANT TOJEDEC STANDARDS MO-220-WGGC.
0.02 NOM
0.20 REF
0.20 MIN
0.25 FOR PROPER CONNECTION OF
Figure 22. 16-Lead Lead Frame Chip Scale Package [LFCSP_WQ] 2 Operating at extended temperatures over prolonged periods may shorten the lifetime performance of the part.
Rev. 0 | Page 24 of 24 NOTES ©2012 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D09012-0-12/12(0)