Automotive, ±1°C Accurate, 16-Bit, 175°C,
Digital SPI Temperature Sensor in Die Form
ADT7312
Rev. 0
rights of third parties that may result from its use. Specifications subject to change without notice. No
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TEMPERATURE
VALUE
REGISTER
CONFIGURATION STATUS
REGISTER
ID
REGISTER
REGISTER
T
HYST
REGISTER
T
LOW
REGISTER
T
HIGH
REGISTER
T
CRIT
REGISTER
INTERNAL
REFERENCE
7
TEMPERATURE
SENSOR
T
HIGH
T
CRIT
T
LOW
INTERNAL
OSCILLATOR
FILTER
LOGIC
Σ-Δ
MODULATOR
GND
8
GND
9
V
DD
10
V
DD
6
5
CT
INT
3
4
1
2
SPI INTERFACE
ADT7312
06791-001
SCLK
DOUT
DIN
CS
Data Sheet
FEATURES
Qualified for automotive applications
High performance
Temperature accuracy:
±1°C from −55°C to +175°C (2.7 V to 3.3 V)
16-bit temperature resolution: 0.0078°C
Fast first temperature conversion on power-up of 6 ms
Easy implementation
No temperature calibration or correction required
No linearity correction required
Low power
Power-saving 1 sample per second (SPS) mode
880 μW typical at 3.6 V in normal mode
9 μW typical at 3.6 V in shutdown mode
Wide operating ranges
Temperature range: −55°C to +175°C
Voltage range: 2.7 V to 5.5 V
Programmable interrupts
Critical overtemperature interrupt
Overtemperature/undertemperature interrupt
SPI-compatible interface
Available in die form only
APPLICATIONS
Automotive
High temperature monitoring
High temperature thermal protection
FUNCTIONAL BLOCK DIAGRAM
GENERAL DESCRIPTION
The ADT7312 is a ±1°C accurate digital temperature sensor
that operates over a very wide temperature range of −55°C to
+175°C and is available in die form only. It contains an internal
band gap reference, a temperature sensor, and a 16-bit analogto-digital converter (ADC) to monitor and digitize the temperature to a resolution of 0.0078°C. The default ADC resolution
is 13 bits (0.0625°C). The ADC resolution can be changed to
16 bits (0.0078°C) using the serial interface.
The ADT7312 is guaranteed to operate over supply voltages
from 2.7 V to 5.5 V. At 3.6 V operation, the average supply
current is typically 245 μA. The ADT7312 has a shutdown
mode that powers down the device, resulting in a typical
shutdown current of 2.5 μA at 3.6 V. The ADT7312 is rated
for operation over the −55°C to +175°C temperature range.
The CT pin is an open-drain output that becomes active when
the temperature exceeds a programmable critical temperature
limit. The default critical temperature limit is 147°C. The INT
pin is also an open-drain output that becomes active when the
temperature exceeds a programmable limit. The INT pin and
the CT pin can operate in either comparator or interrupt mode.
PRODUCT HIGHLIGHTS
1. Ease of use, no calibration or correction required.
2. Low power consumption.
3. Excellent long-term stability and reliability.
4. Qualified for automotive applications.
Figure 1.
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One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 www.analog.com
ADT7312 Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Product Highlights ........................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
SPI Timing Specifications ........................................................... 4
Absolute Maximum Ratings ............................................................ 5
ESD Caution .................................................................................. 5
Pad Configuration and Function Descriptions ............................ 6
Die Bond Pad Coordinates .............................................................. 7
Typical Performance Characteristics ............................................. 8
Theory of Operation ........................................................................ 9
Circuit Description....................................................................... 9
Converter Architecture ................................................................ 9
Normal Mode (Continuous Conversion Mode) ...................... 9
One-Shot Mode .......................................................................... 10
1 SPS Mode .................................................................................. 11
Shutdown Mode .......................................................................... 11
Fault Queue ................................................................................. 11
Temperature Data Format ......................................................... 12
Temperature Conversion Formulas ......................................... 12
Registers ........................................................................................... 13
Status Register ............................................................................. 13
Configuration Register .............................................................. 14
Temperature Value Register ...................................................... 15
ID Register................................................................................... 15
T
Setpoint Register ............................................................... 15
CRIT
T
Setpoint Register ............................................................... 16
HYST
T
Setpoint Register .............................................................. 16
HIGH
T
Setpoint Register ............................................................... 16
LOW
Serial Interface ................................................................................ 17
SPI Command Byte .................................................................... 17
Writing Data ............................................................................... 18
Reading Data ............................................................................... 19
Interfacing to DSPs or Microcontrollers ................................. 19
Resetting the Serial Interface .................................................... 19
INT and CT Outputs ...................................................................... 20
Undertemperature and Overtemperature Detection ............ 20
Redundant Critical Generator .................................................. 21
Applications Information .............................................................. 22
Thermal Response Time ........................................................... 22
Supply Decoupling ..................................................................... 22
Powering from a Switching Regulator ..................................... 22
Temperature Monitoring ........................................................... 22
Quick Guide to Measuring Temperature ................................ 22
Outline Dimensions ....................................................................... 23
Ordering Guide .......................................................................... 23
Automotive Products ................................................................. 23
REVISION HISTORY
1/12—Revision 0: Initial Version
Rev. 0 | Page 2 of 24
Data Sheet ADT7312
Accuracy1
±1.0
°C
TA = −55°C to +175°C, VDD = 2.7 V to 3.3 V
Temperature Conversion Time
240 ms
Continuous and one-shot conversion modes
Input High Voltage, VIH
0.7 × VDD
V
1 SPS Mode
55 µA
VDD = 3.6 V, TA = 25°C
SPECIFICATIONS
TA = −55°C to +175°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
±1.1 °C TA = −55°C to +175°C, VDD = 3.3 V to 3.6 V
±1.2 °C TA = +150°C to +175°C, VDD = 4.5 V to 5.5 V
±1.5 °C TA = −55°C to +175°C, VDD = 4.5 V to 5.5 V
ADC Resolution 13 Bits
16 Bits
Temperature Resolution
13-Bit 0.0625 °C 13-bit resolution (sign bit plus 12 bits)
16-Bit 0.0078 °C 16-bit resolution (sign bit plus 15 bits)
Fast Temperature Conversion Time 6 ms First conversion on power-up only
1 SPS Conversion Time 60 ms 1 SPS mode
Temperature Hysteresis ±0.002 °C
Repeatability2 ±0.015 °C TA = 25°C
DC PSRR 0.1 °C/V TA = 25°C
DIGITAL OUTPUTS (CT, INT) Open-drain outputs
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, C
DIGITAL INPUTS (DIN, SCLK, CS)
2 pF
OUT
Input Current, IIN ±1 µA VIN = 0 V to VDD
Input Low Voltage, VIL 0.4 V
Twos complement temperature value of sign bit
plus 12 bits (power-on default resolution)
Twos complement temperature value of sign bit
plus 15 bits (Bit 7 = 1 in the configuration register)
Pin Capacitance, CIN 5 10 pF
DIGITAL OUTPUT (DOUT)
Output High Voltage, VOH VDD − 0.3 V I
SOURCE
= I
= 200 µA
SINK
Output Low Voltage, VOL 0.4 V IOL = 200 µA
Output Capacitance, C
50 pF
OUT
POWER REQUIREMENTS
Supply Voltage 2.7 5.5 V
Supply Current Peak current while converting; SPI interface inactive
Continuous Conversion Mode 245 320 µA VDD = 3.6 V
275 350 µA VDD = 5.5 V
70 µA VDD = 5.5 V, TA = 25°C
Shutdown Mode 2.5 40 µA VDD = 3.6 V
5.4 50 µA VDD = 5.5 V
Power Dissipation Power dissipated for VDD = 3.6 V, TA = 25°C
Continuous Conversion Mode 880 µW
1 SPS Mode 200 µW
Shutdown Mode 9 µW
1
Accuracy includes lifetime drift.
2
Based on a floating average of 10 readings.
Rev. 0 | Page 3 of 24
ADT7312 Data Sheet
t8 0 ns min
CS
SCLK
DIN
DOUT
t
1
1
8
76
MSB LSB
2 3
MSB
LSB
9 10 23 24
t
2
t
4
t
5
t
3
t
6
t
7
t
8
t
9
t
10
06791-002
SPI TIMING SPECIFICATIONS
TA = −55°C to +175°C, VDD = 2.7 V to 5.5 V, unless otherwise noted. All input signals are specified with rise time (tR) = fall time (tF) = 5 ns
(10% to 90% of V
) and timed from a voltage level of 1.6 V.
DD
Table 2.
Parameter
t1 0 ns min
1, 2
Limit at T
MIN
, T
Unit Description
MAX
CS falling edge to SCLK active edge setup time
t2 100 ns min SCLK high pulse width
t3 100 ns min SCLK low pulse width
t4 30 ns min Data setup time prior to SCLK rising edge
t5 25 ns min Data hold time after SCLK rising edge
t6 5 ns min Data access time after SCLK falling edge
60 ns max VDD = 4.5 V to 5.5 V
80 ns max VDD = 2.7 V to 3.6 V
3
t
10 ns min
7
Bus relinquish time after
CS inactive edge
80 ns max
SCLK inactive edge to CS rising edge hold time
t9 0 ns min
CS falling edge to DOUT active time
60 ns max VDD = 4.5 V to 5.5 V
80 ns max VDD = 2.7 V to 3.6 V
t10 10 ns min SCLK inactive edge to DOUT low
1
Sample tested during initial release to ensure compliance.
2
See Figure 2.
3
The t7 values are the true bus relinquish times of the part and, as such, are independent of external bus loading capacitances.
Figure 2. Detailed SPI Timing Diagram
Rev. 0 | Page 4 of 24
Data Sheet ADT7312
DIN Input Voltage to GND
−0.3 V to VDD + 0.3 V
Operating Temperature Range
−55°C to +175°C
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Rating
VDD to GND −0.3 V to +7 V
DOUT Output Voltage to GND −0.3 V to VDD + 0.3 V
SCLK Input Voltage to GND −0.3 V to VDD + 0.3 V
175°C
JMAX
−0.3 V to V
CS Input Voltage to GND
CT and INT Output Voltage to GND −0.3 V to VDD + 0.3 V
ESD Rating (Human Body Model) 2.0 kV
Storage Temperature Range −65°C to +175°C
Maximum Junction Temperature, T
+ 0.3 V
DD
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
Rev. 0 | Page 5 of 24
ADT7312 Data Sheet
PAD CONFIGURATION AND FUNCTION DESCRIPTIONS
1950µm
SCLK
DOUT
2350µm
DIN
CS
Figure 3. Metallization Picture
V
DD
V
DD
GND
GND
CT
INT
06791-004
Table 4. Pad Function Descriptions
Pad No. Pad Name Description
1 SCLK Serial Clock Input. The serial clock is used to clock data into and out of any register of the device.
2 DOUT Serial Data Output. Data is clocked out on the falling edge of SCLK and is valid on the rising edge of SCLK.
3 DIN
Serial Data Input. Data to be loaded into the control registers of the part is provided on this input. Data is clocked
into the registers on the rising edge of SCLK.
4
CS
5 INT
Chip Select Input. The device is enabled when this pin is low. The device is disabled when this pin is high.
Overtemperature and Undertemperature Indicator. Logic output. When the device is powered up, this output is an
active low interrupt by default. Open-drain configuration. A pull-up resistor is required, typically 10 kΩ.
6 CT
Critical Overtemperature Indicator. Logic output. The default power-on polarity is active low. Open-drain
configuration. A pull-up resistor is required, typically 10 kΩ.
7 GND Analog Ground. This pad must be connected directly to Pad 8 (digital ground).
8 GND Digital Ground. This pad must be connected directly to Pad 7 (analog ground).
9 VDD
Analog Supply Voltage (2.7 V to 5.5 V). This pad must be connected directly to Pad 10 (digital supply voltage). The
supply should be decoupled with a 0.1 μF ceramic capacitor to GND.
10 VDD
Digital Supply Voltage (2.7 V to 5.5 V). This pad must be connected directly to Pad 9 (analog supply voltage). The
supply should be decoupled with a 0.1 μF ceramic capacitor to GND.
Rev. 0 | Page 6 of 24
Data Sheet ADT7312
2
DOUT
−838
+831
7
GND
+838
+508
DIE BOND PAD COORDINATES
The following X and Y coordinates refer to the center of the bond pad and are referenced from the center of the die.
Table 5. Bond Pad Coordinates
Pad No. Pad Name X Coordinate (µm) Y Coordinate (µm)
1 SCLK −838 +1020
3 DIN −838 −863
4
5 INT +838 −1011
6 CT +838 −863
8 GND +838 +702
9 VDD +838 +857
10 VDD +838 +1008
CS
−838 −1011
Rev. 0 | Page 7 of 24
ADT7312 Data Sheet
–50–70 –30 –10 10 30 50 70 90 110 130 150
170
190
TEMPERAT URE E RROR (ºC)
TEMPERATURE (ºC)
06791-005
–0.4
–0.6
–0.8
–0.2
0
0.4
0.2
0.6
0.8
1.0
–50–70 –30 –10 10 30 50
70 90 110 130 150
170
190
TEMPERATURE ERROR (ºC)
TEMPERATURE (ºC)
06791-006
–1.0
–0.5
0
0.5
1.0
1.5
350
300
200
250
150
100
50
0
–60 –40 –20 0 20 40 60 80 100 120 140 160 180
I
DD
(µA)
TEMPERATURE (°C)
5V CONTINUOUS CONVERSI ON
3V CONTINUOUS CONVERSI ON
5V 1SPS
3V 1SPS
06791-007
0
5
10
15
20
25
30
–60 –40 –20 0 20 40 60 80 100 120 140 160 180
SHUTDOWN I
DD
(µA)
TEMPERATURE (°C)
06791-008
V
DD
= 2.7V
V
DD
= 3.0V
V
DD
= 3.6V
V
DD
= 4.5V
V
DD
= 5.0V
V
DD
= 5.5V
0
50
100
150
200
250
300
2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
I
DD
(µA)
SUPPLY VOLTAGE (V)
CONTINUO US CONVERSION
06791-009
1SPS
0
1
2
3
4
5
6
2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
SHUTDOWN I
DD
(µA)
SUPPLY VOLTAGE (V)
06791-010
TYPICAL PERFORMANCE CHARACTERISTICS
Figure 4. Temperature Accuracy at 3 V
Figure 7. Shutdown Current vs. Temperature
Figure 5. Temperature Accuracy at 5 V
Figure 6. Operating Supply Current vs. Temperature
Figure 8. Operating Supply Current vs. Supply Voltage
Figure 9. Shutdown Current vs. Supply Voltage
Rev. 0 | Page 8 of 24
Data Sheet ADT7312
Σ-Δ MODUL ATOR
INTEGRATOR
COMPARATOR
TEMPERATURE
VALUE
REGISTER
CLOCK
GENERATOR
VOLTAGE
REFERENCE
LPF DIGITAL
FILTER
1-BIT
DAC
1 BIT
13/16 BITS
06791-011
THEORY OF OPERATION
CIRCUIT DESCRIPTION
The ADT7312 is a ±1°C accurate digital temperature sensor
that uses a 16-bit ADC to monitor and digitize the temperature
to a resolution of 0.0078°C. By default, the ADC resolution is
set to 13 bits (0.0625°C).
An internal temperature sensor generates a voltage proportional
to absolute temperature; this voltage is compared to an internal
voltage reference and input into a precision digital modulator.
The internal temperature sensor has high accuracy and linearity
over the entire rated temperature range without the need for
correction or calibration by the user.
The sensor output is digitized by a sigma-delta (Σ-∆) modulator, also known as a charge balance type ADC. This type of
converter uses time domain oversampling and a high accuracy
comparator to deliver 16 bits of resolution in an extremely
compact circuit.
CONVERTER ARCHITECTURE
The Σ-∆ modulator consists of an input sampler, a summing
network, an integrator, a comparator, and a 1-bit digital-toanalog converter (DAC). This architecture creates a negative
feedback loop and minimizes the integrator output by changing
the duty cycle of the comparator output in response to input
voltage changes. The comparator samples the output of the
integrator at a much higher rate than the input sampling frequency. This oversampling spreads the quantization noise over
a much wider band than that of the input signal, improving
overall noise performance and increasing accuracy.
The modulated output of the comparator is encoded using
a circuit technique that results in SPI temperature data.
The ADT7312 can be configured to operate in any one of the
following operating modes:
• Normal mode (continuous conversion mode)
• One-shot mode
• 1 SPS mode
• Shutdown mode
NORMAL MODE (CONTINUOUS CONVERSION MODE)
In normal mode (default power-on mode), the ADT7312 runs
an automatic conversion sequence. During this automatic conversion sequence, a conversion typically takes 240 ms to complete.
The ADT7312 is continuously converting: as soon as one temperature conversion is completed, another temperature conversion
begins. Each temperature conversion result is stored in the
temperature value register (Register Address 0x02) and is available through the SPI interface. In continuous conversion mode,
the read operation provides the most recent converted result.
On power-up, the first conversion is a fast conversion, taking
typically 6 ms. If the temperature exceeds 147°C, the CT pin is
asserted low. If the temperature exceeds 64°C, the INT pin is
asserted low. Fast conversion temperature accuracy is typically
within ±5°C.
The conversion clock for the part is generated internally. No
external clock is required except when reading from and
writing to the serial port.
The measured temperature value is compared with a critical
temperature limit (stored in the 16-bit T
a high temperature limit (stored in the 16-bit T
register), and a low temperature limit (stored in the 16-bit T
setpoint register). If the measured value exceeds the T
T
limit, the INT pin is activated; if the measured value
LOW
exceeds the T
limit, the CT pin is activated. The polarity of
CRIT
the INT and CT pins is programmable using the configuration
register (Register Address 0x01). The INT and CT pins are also
programmable for interrupt mode via the configuration register.
setpoint register),
CRIT
setpoint
HIGH
HIGH
LOW
or
Figure 10. Σ-∆ Modulator
Rev. 0 | Page 9 of 24
ADT7312 Data Sheet
DIN
0x08 0x20
DATA
SCLK
DOUT
CS
WAIT 240ms MINIMUM
FOR CONVERSION TO FINISH
06791-012
ONE-SHOT MODE
When one-shot mode is enabled, the ADT7312 immediately
completes a conversion and then goes into shutdown mode.
The one-shot mode is useful when one of the circuit design
priorities is to reduce power consumption.
To enable one-shot mode, set Bits[6:5] of the configuration register (Register Address 0x01) to 01. After writing to the operation
mode bits (Bits[6:5]), wait at least 240 ms before reading back the
temperature from the temperature value register (see Figure 11).
This delay ensures that the ADT7312 has adequate time to power
up and complete a conversion.
To obtain an updated temperature conversion, reset Bits[6:5]
of the configuration register to 01.
CT and INT Operation in One-Shot Mode
Figure 12 illustrates the operation of the CT pin in one-shot
mode when the T
overtemperature limit is exceeded. Note
CRIT
that in interrupt mode, a read from any register resets the CT
and INT pins. (For more information about interrupt mode and
comparator mode, see the Undertemperature and Overtemperature
Detection section.)
If the INT pin is configured for comparator mode and the
temperature falls below the T
T
+ T
LOW
value, a write to the operation mode bits of the
HYST
HIGH
− T
value or exceeds the
HYST
configuration register (Register Address 0x01, Bits[6:5] = 01)
resets the INT pin.
If the CT pin is configured for comparator mode and the
temperature falls below the T
CRIT
− T
value, a write to the
HYST
operation mode bits of the configuration register (Register
Address 0x01, Bits[6:5] = 01) resets the CT pin (see Figure 12).
When using one-shot mode, ensure that the refresh rate is
appropriate to the application being used.
Figure 11. Typical SPI One-Shot Write to Configuration Register Followed by a Read from the Temperature Value Register
Rev. 0 | Page 10 of 24
Data Sheet ADT7312
TEMPERATURE
149°C
148°C
147°C
146°C
145°C
144°C
143°C
142°C
141°C
140°C
139°C
CT PIN
POLARITY =
ACTIVE LOW
CT PIN
POLARITY =
ACTIVE HIGH
T
CRIT
– T
HYST
T
CRIT
TIME
06791-013
WRITE 01 TO
BITS[6:5] OF
CONFIGURATION
REGISTER*
WRITE 01 TO
BITS[6:5] OF
CONFIGURATION
REGISTER*
WRITE 01 TO
BITS[6:5] OF
CONFIGURATION
REGISTER*
*AFTER WRITING TO THE CONFIGURATION REGISTERTO START A ONE-SHOT
CONVERSION, THE CO NV E RS ION TIM E IS 240ms. THEREFORE, I T TAKES AT
LEAST 240ms AFTER THE WRITETO THE CONFIGURATION REGISTER
BEFORE T HE CT PIN BECOM E S ACTIVE.
Figure 12. CT Pin Operation in One-Shot Mode
1 SPS MODE
In 1 SPS mode, the part performs one measurement per second.
A conversion takes only 60 ms, and the part remains in the idle
state for the remaining 940 ms period. To enable 1 SPS mode, set
Bits[6:5] of the configuration register (Register Address 0x01)
to 10.
SHUTDOWN MODE
The ADT7312 can be placed in shutdown mode by setting Bits[6:5]
of the configuration register (Register Address 0x01) to 11. The
ADT7312 can be taken out of shutdown mode by setting Bits[6:5]
to 00 in the configuration register. The ADT7312 typically takes
1 ms (with a 0.1 µF decoupling capacitor) to come out of shutdown
mode. The conversion result from the last conversion prior to
shutdown can still be read from the ADT7312 even when it is
in shutdown mode.
When the part is taken out of shutdown mode, the internal clock
is restarted and a conversion is initiated.
FAULT QUEUE
Bits[1:0] of the configuration register (Register Address 0x01)
are used to configure the fault queue. Up to four faults are provided to prevent false tripping of the INT and CT pins when
the ADT7312 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 fault queue is set to four, four consecutive
temperature conversion results must exceed a temperature
limit before the INT or CT pin is activated. If two consecutive
temperature conversions exceed a temperature limit but the
third conversion does not exceed a limit, the fault count is reset
to zero.
Rev. 0 | Page 11 of 24
ADT7312 Data Sheet
−55°C
1 1100 1001 0000
0x1C90
TEMPERATURE DATA FORMAT
One LSB of the ADC corresponds to 0.0078°C in 16-bit mode.
The ADC can theoretically measure a temperature range of
255°C, but the ADT7312 is guaranteed to measure a low value
temperature limit of −55°C to a high value temperature limit of
+175°C. The temperature measurement result is stored in the
16-bit temperature value register (Register Address 0x02). It is
compared with the high temperature limits stored in the T
setpoint register and the T
setpoint register. The temperature
HIGH
measurement result is also compared with the low temperature
limit stored in the T
setpoint register.
LOW
Temperature data in the temperature value register, the T
setpoint register, the T
setpoint register, and the T
HIGH
LOW
register is represented by a 13-bit, twos complement word. The
MSB is the temperature sign bit. When the part is powered up, the
three LSBs, Bits[2:0], are not part of the temperature conversion
result, but are flag bits for T
CRIT
, T
HIGH
, and T
. Tabl e 6 shows
LOW
the 13-bit temperature data format without Bits[2:0].
Table 6. 13-Bit Temperature Data Format
Digital Output (Bits[D15:D3])
Temperature
−50°C 1 1100 1110 0000 0x1CE0
−25°C 1 1110 0111 0000 0x1E70
−0.0625°C 1 1111 1111 1111 0x1FFF
0°C 0 0000 0000 0000 0x0000
+0.0625°C 0 0000 0000 0001 0x0001
+25°C 0 0001 1001 0000 0x0190
+50°C 0 0011 0010 0000 0x0320
+125°C 0 0111 1101 0000 0x07D0
+150°C 0 1001 0110 0000 0x0960
+175°C 0 1010 1111 0000 0x0AF0
Binary Hex
The number of bits in the temperature data-word can be
extended to 16 bits, twos complement, by setting Bit 7 of the
configuration register (Register Address 0x01) to 1. When using
a 16-bit temperature data value, Bits[2:0] are the LSBs of the
temperature value. The default power-on configuration is a
13-bit temperature data value.
Reading back the temperature from the temperature value
register requires a 2-byte read. Designers who use a 9-bit temperature data format can still use the ADT7312 by ignoring the
four LSBs of the 13-bit temperature value. These four LSBs are
Bits[6:3] in Tabl e 6.
CRIT
CRIT
setpoint
TEMPERATURE CONVERSION FORMULAS
16-Bit Temperature Data Format
Positive Temperature = ADC Code (dec)/128
Negative Temperature = (ADC Code (dec) − 65,536)/128
where ADC Code uses all 16 bits of the data byte, including the
sign bit.
Negative Temperature = (ADC Code (dec) − 32,768)/128
where the MSB is removed from the ADC code.
13-Bit Temperature Data Format
Positive Temperature = ADC Code (dec)/16
Negative Temperature = (ADC Code (dec) − 8192)/16
where ADC Code uses all 13 bits of the data byte, including the
sign bit.
Negative Temperature = (ADC Code (dec) − 4096)/16
where the MSB is removed from the ADC code.
10-Bit Temperature Data Format
Positive Temperature = ADC Code (dec)/2
Negative Temperature = (ADC Code (dec) − 1024)/2
where ADC Code uses all 10 bits of the data byte, including the
sign bit.
Negative Temperature = (ADC Code (dec) − 512)/2
where the MSB is removed from the ADC code.
9-Bit Temperature Data Format
Positive Temperature = ADC Code (dec)
Negative Temperature = ADC Code (dec) − 512
where ADC Code uses all nine bits of the data byte, including
the sign bit.
Negative Temperature = ADC Code (dec) − 256
where the MSB is removed from the ADC code.
Rev. 0 | Page 12 of 24
Data Sheet ADT7312
0x04
T
setpoint
0x4980 (147°C)
REGISTERS
The ADT7312 contains eight registers.
• Status register
• Configuration register
• Temperature value register
• ID register
• Four temperature setpoint registers
The status register, the temperature value register, and the ID
register are read-only registers.
Table 7. ADT7312 Registers
Register
Address Register Name Power-On Default
0x00 Status 0x80
0x01 Configuration 0x00
0x02 Temperature value 0x0000
0x03 ID 0xC3
CRIT
0x05 T
0x06 T
0x07 T
setpoint 0x05 (5°C)
HYST
setpoint 0x2000 (64°C)
HIGH
setpoint 0x0500 (10°C)
LOW
STATUS REGISTER
The 8-bit, read-only status register (Register Address 0x00)
reflects the status of the overtemperature and undertemperature
interrupts that can activate the CT and INT pins. This register
also reflects the status of a temperature conversion operation.
The interrupt flags in the status register (Bits[6:4]) are reset by
a read of the register or when the temperature value returns
within the temperature limits (including hysteresis). The
bit (Bit 7) is reset to 1 after a read of the temperature value
register (Register Address 0x02). In one-shot and 1 SPS modes,
RDY
the
bit is reset after a write to the operation mode bits of
the configuration register (Register Address 0x01, Bits[6:5]).
RDY
Table 8. Status Register (Register Address 0x00)
Bits Default Value Type Name Description
7 1 R
RDY This bit is set to 0 when the temperature conversion result is written to the
temperature value register. This bit is reset to 1 when the temperature value register
is read. In one-shot and 1 SPS modes, this bit is reset after a write to the operation
mode bits of the configuration register (Register Address 0x01, Bits[6:5]).
6 0 R T
CRIT
This bit is set to 1 when the temperature exceeds the T
is cleared to 0 when the status register is read or when the measured temperature
falls below the limit (T
5 0 R T
HIGH
This bit is set to 1 when the temperature exceeds the T
is cleared to 0 when the status register is read or when the measured temperature
falls below the limit (T
4 0 R T
LOW
This bit is set to 1 when the temperature goes below the T
bit is cleared to 0 when the status register is read or when the measured temperature
rises above the limit (T
[3:0] 0000 R Unused Reads back 0000.
CRIT
HIGH
LOW
− T
− T
+ T
) set in the T
HYST
) set in the T
HYST
) set in the T
HYST
setpoint and T
CRIT
setpoint and T
HIGH
setpoint and T
LOW
temperature limit. This bit
CRIT
setpoint registers.
HYST
temperature limit. This bit
HIGH
setpoint registers.
HYST
temperature limit. This
LOW
registers.
HYST
Rev. 0 | Page 13 of 24
ADT7312 Data Sheet
CONFIGURATION REGISTER
The 8-bit, read/write configuration register (Register Address 0x01)
stores configuration values for the ADT7312. Configuration
Table 9. Configuration Register (Register Address 0x01)
Bits Default Value Type Name Description
7 0
[6:5] 00
4 0
3 0
2 0
[1:0] 00
R/
R/
R/
R/
R/
R/
Resolution This bit sets the resolution of the ADC when converting.
W
0 = 13-bit resolution (default). The sign bit plus 12 bits gives a temperature
resolution of 0.0625°C.
1 = 16-bit resolution. The sign bit plus 15 bits gives a temperature resolution
of 0.0078°C.
Operation mode These two bits set the operational mode for the ADT7312.
W
00 = continuous conversion mode (default). After one conversion is finished,
the ADT7312 begins the next conversion. Conversion time is 240 ms typical.
01 = one-shot mode. Conversion time is 240 ms typical.
10 = 1 SPS mode. Conversion time is 60 ms typical. This operational mode
reduces the average current consumption.
11 = shutdown mode. All circuitry except for the interface circuitry is powered
down.
INT/CT mode This bit selects comparator mode or interrupt mode.
W
0 = interrupt mode.
1 = comparator mode.
INT pin polarity This bit selects the output polarity of the INT pin.
W
0 = active low.
1 = active high.
CT pin polarity This bit selects the output polarity of the CT pin.
W
0 = active low.
1 = active high.
Fault queue
W
These two bits set the number of consecutive undertemperature or overtemperature faults that must occur before the INT and CT pins are activated. The fault
queue helps to avoid false triggering due to temperature noise.
00 = 1 fault (default).
01 = 2 faults.
10 = 3 faults.
11 = 4 faults.
values include the ADC resolution, the operational mode of the
part, interrupt pin mode and polarity, and the depth of the fault
queue for overtemperature and undertemperature events.
Rev. 0 | Page 14 of 24
Data Sheet ADT7312
2 0 R
T
flag/LSB 2
[2:0]
011 R Revision ID
Contains the silicon revision identification number.
TEMPERATURE VALUE REGISTER
The 16-bit, read-only temperature value register (Register
Address 0x02) stores the temperature measured by the internal
temperature sensor. The temperature is stored as a 16-bit, twos
complement value. The temperature is read back from the
temperature value register as a 16-bit value.
When the ADC is configured to convert the temperature to
a 13-bit digital value, Bits[2:0] are event alarm flags for T
T
HIGH
, and T
. When the ADC is configured to convert the
LOW
temperature to a 16-bit digital value, Bits[2:0] are the LSBs of
the extended digital value. To configure the ADC for 13-bit
or 16-bit resolution, write to Bit 7 of the configuration register
(Register Address 0x01).
Table 10. Temperature Value Register (Register Address 0x02)
Bits Default Value Type Name Description
15 0 R Sign
[14:8] 0000000 R Temp Temperature value (Bits[14:8]) in twos complement format.
[7:3] 00000 R Temp Temperature value (Bits[7:3]) in twos complement format.
CRIT
1 0 R T
0 0 R T
flag/LSB 1
HIGH
flag/LSB 0
LOW
,
CRIT
Sign bit. Indicates whether the temperature value is negative or positive
(0 = positive, 1 = negative).
If the part is configured for 13-bit resolution (Register Address 0x01, Bit 7 = 0), this
bit flags a critical overtemperature event. When the temperature value exceeds
T
, this bit is set to 1. If the part is configured for 16-bit resolution (Register
CRIT
Address 0x01, Bit 7 = 1), this bit is LSB 2 of the 15-bit temperature value.
If the part is configured for 13-bit resolution (Register Address 0x01, Bit 7 = 0), this
bit flags an overtemperature event. When the temperature value exceeds T
this bit is set to 1. If the part is configured for 16-bit resolution (Register Address
0x01, Bit 7 = 1), this bit is LSB 1 of the 15-bit temperature value.
If the part is configured for 13-bit resolution (Register Address 0x01, Bit 7 = 0), this
bit flags an undertemperature event. When the temperature value falls below
, this bit is set to 1. If the part is configured for 16-bit resolution (Register
T
LOW
Address 0x01, Bit 7 = 1), this bit is LSB 0 of the 15-bit temperature value.
ID REGISTER
The 8-bit, read-only ID register (Register Address 0x03) stores the
manufacturer ID in Bits[7:3] and the silicon revision in Bits[2:0].
T
SETPOINT REGISTER
CRIT
The 16-bit, read/write T
Address 0x04) stores the critical overtemperature limit value.
A critical overtemperature event occurs when the temperature
value stored in the temperature value register exceeds the value
stored in this register. The CT pin is activated if a critical overtemperature event occurs. The temperature is stored in twos
complement format; the MSB is the temperature sign bit.
The default setting for the T
setpoint register (Register
CRIT
setpoint is +147°C.
CRIT
HIGH
,
Table 11. ID Register (Register Address 0x03)
Bits Default Value Type Name Description
[7:3] 11000 R Manufacturer ID Contains the manufacturer identification number.
Table 12. T
Setpoint Register (Register Address 0x04)
CRIT
Bits Default Value Type Name Description
[15:0] 0x4980
W
R/
T
CRIT
16-bit critical overtemperature limit, stored in twos complement format. The
default setting is +147°C.
Rev. 0 | Page 15 of 24
ADT7312 Data Sheet
T
SETPOINT REGISTER
HYST
The 8-bit, read/write T
stores the temperature hysteresis value for the T
T
temperature limits. The temperature hysteresis value is
CRIT
setpoint register (Register Address 0x05)
HYST
, T
HIGH
LOW
, and
stored in straight binary format using the four LSBs. Each LSB
increments the hysteresis value in steps of 1°C from 0°C to 15°C.
To implement hysteresis, the value in this register is subtracted
from the T
The default setting for the T
T
SETPOINT REGISTER
HIGH
The 16-bit, read/write T
HIGH
and T
values and is added to the T
CRIT
setpoint is +5°C.
HYST
setpoint register (Register
HIGH
LOW
value.
Address 0x06) stores the overtemperature limit value. An
overtemperature event occurs when the temperature value
stored in the temperature value register exceeds the value
stored in this register. The INT pin is activated if an overtemperature event occurs. The temperature is stored in twos
complement format; the MSB is the temperature sign bit.
The default setting for the T
T
SETPOINT REGISTER
LOW
The 16-bit, read/write T
setpoint is +64°C.
HIGH
setpoint register (Register
LOW
Address 0x07) stores the undertemperature limit value. An
undertemperature event occurs when the temperature value
stored in the temperature value register is less than the value
stored in this register. The INT pin is activated if an undertemperature event occurs. The temperature is stored in twos
complement format; the MSB is the temperature sign bit.
The default setting for the T
setpoint is +10°C.
LOW
Table 13. T
Setpoint Register (Register Address 0x05)
HYST
Bits Default Value Type Name Description
[7:4] 0000
[3:0] 0101
R/
R/
Unused Not used.
W
T
W
HYST
Hysteresis value, from 0°C to +15°C, stored in straight binary format. The default
setting is +5°C.
Table 14. T
Setpoint Register (Register Address 0x06)
HIGH
Bits Default Value Type Name Description
[15:0] 0x2000
R/
W
T
HIGH
16-bit overtemperature limit, stored in twos complement format. The default
setting is +64°C.
Table 15. T
Setpoint Register (Register Address 0x07)
LOW
Bits Default Value Type Name Description
[15:0] 0x0500
R/
W
T
LOW
16-bit undertemperature limit, stored in twos complement format. The default
setting is +10°C.
Rev. 0 | Page 16 of 24
Data Sheet ADT7312
ADT7312
GND
SCLK
DOUT
DIN
CT
INT
V
DD
10kΩ10kΩ
PULL-UP
TO V
DD
0.1µF
MICROCONTROLLER
V
DD
CS
06791-023
SERIAL INTERFACE
Figure 13. Typical SPI Interface Connection
The ADT7312 has a 4-wire serial peripheral interface (SPI).
The interface has a data input pin (DIN) for writing data to the
device, a data output pin (DOUT) for reading data back from
the device, and a data clock pin (SCLK) for clocking data into
and out of the device. A chip select pin (
the ADT7312.
CS
is required for correct operation of the serial
CS
) enables or disables
interface. Data is clocked out of the ADT7312 on the falling
edge of SCLK; data is clocked into the device on the rising edge
of SCLK.
SPI COMMAND BYTE
All data transactions on the bus begin with the master taking
CS
from high to low and sending out the command byte. The
command byte indicates to the ADT7312 whether the transaction
is a read or a write and provides the address of the register for
the data transfer. Tabl e 16 shows the command byte.
Table 16. Command Byte
C7 C6 C5 C4 C3 C2 C1 C0
0
W
R/
Register address 0 0 0
Bit C7, Bit C2, Bit C1, and Bit C0 of the command byte must all
be set to 0 to successfully begin a bus transaction. The SPI interface does not work correctly if a 1 is written to any of these bits.
Bit C6 is the read/write bit: 1 indicates a read, and 0 indicates
a write.
Bits[C5:C3] contain the target register address. One register can
be read from or written to per bus transaction.
Rev. 0 | Page 17 of 24
ADT7312 Data Sheet
SCLK
WRITING DATA
Data is written to the ADT7312 in 8 bits or 16 bits, depending
on the addressed register. The first byte written to the device is
the command byte, with the read/write bit set to 0. The master
then supplies the 8-bit or 16-bit input data on the DIN line.
The ADT7312 clocks the data into the register addressed in the
command byte on the rising edge of SCLK. The master ends the
write transaction by pulling
CS
CS
high.
Figure 14 shows a write to an 8-bit register, and Figure 15 shows
a write to a 16-bit register.
The master must begin a new write transaction on the bus, for
every register write. Only one register is written to per bus
transaction.
SCLK
DIN
1234
8-BIT COMMAND BYTE
0
R/W REGIST ER ADDR
C4
C5
C6
C7
5 6 7 8 9 10111213141516
8-BIT DATA
000
C3
C2
C0
C1
D4 D3D7 D6
D5
D2 D1 D0
6791-015
Figure 14. Writing to an 8-Bit Register
CS
22 23
06791-016
DIN
1234
8-BIT COMM AND BYTE
0
R/W REGISTER ADDR
C7 C6 C1 D2 D1 D0
5246 7 8 9 10 11 12 13 14 15 16
16-BIT DATA
00
0
C3 C2C5 C4
C0
D14 D13
D12 D10D11 D9 D8 D7D15
17
Figure 15. Writing to a 16-Bit Register
Rev. 0 | Page 18 of 24
Data Sheet ADT7312
CS
READING DATA
A read transaction begins when the master writes the command
byte to the ADT7312 with the read/write bit set to 1. The master
then supplies 8 or 16 clock pulses, depending on the addressed
register, and the ADT7312 clocks data out of the addressed register on the DOUT line. Data is clocked out on the first falling
edge of SCLK following the command byte. The master ends
the read transaction by pulling
CS
high.
Figure 16 shows a read from an 8-bit register, and Figure 17
shows a read from a 16-bit register.
INTERFACING TO DSPs OR MICROCONTROLLERS
The ADT7312 can operate with CS used as a frame synchronization signal. This setup is useful for DSP interfaces. In this case,
the first bit (MSB) is effectively clocked out by
normally occurs after the falling edge of SCLK in DSPs. SCLK
can continue to run between data transfers, provided that the
timing specifications in Table 2 are adhered to.
CS
CS
because CS
can be tied to ground, and the serial interface operated in a
3-wire mode. DIN, DOUT, and SCLK are used to communicate
with the ADT7312 in this mode.
For microcontroller interfaces, it is recommended that SCLK
idle high between data transfers.
RESETTING THE SERIAL INTERFACE
The serial interface can be reset by writing a series of 1s on the
DIN input. If a Logic 1 is written to the ADT7312 DIN line for
at least 32 serial clock cycles, the serial interface is reset. This
ensures that the interface can be reset to a known state if the
connection is lost due to a software error or a glitch in the system.
A reset returns the serial interface to the state in which it waits
for a write to one of the registers in the ADT7312. This operation
resets the contents of all registers to their power-on default values.
Following a reset, the user should allow a delay of 500 μs before
addressing the serial interface.
SCLK
DOUT
CS
DIN
SCLK
DIN
DOUT
1234
0
R/W REGISTER ADDR
C6
C7
C7 C6
8-BIT COMM AND BYTE
C4
C5
23
1
8-BIT COMM AND BYTE
0
R/W REGIS TER ADDR
C5
5
C3
C4
0
C2
6
78
0
C1
9
10
0
C0
D7
D6 D5
4
Figure 16. Reading from an 8-Bit Register
5246 7 8 9 10 11 12 13 14 15 16
0
0
0
C0
C3
C1
C2
D15
D14
D13
D12
D11
D10
Figure 17. Reading from a 16-Bit Register
11 12
8-BIT D ATA
D4
16-BIT DATA
D8 D7
D9
13 14 15
D3 D2 D1 D0
17
16
06791-017
23
22
D1
D2
D0
06791-018
Rev. 0 | Page 19 of 24
ADT7312 Data Sheet
TEMPERATURE
82°C
81°C
80°C
79°C
78°C
77°C
76°C
75°C
74°C
73°C
INT PIN
(COMPARATOR MODE)
POLARITY = ACTIVE LOW
INT PIN
(INTERRUPT MODE)
POLARITY = ACTIVE LOW
INT PIN
(INTERRUPT MODE)
POLARITY = ACTIVE HIGH
INT PIN
(COMPARATOR MODE)
POLARITY = ACTIVE HIGH
T
HIGH
T
HIGH
– T
HYST
TIME
READ
READ READ
06791-020
INT AND CT OUTPUTS
INT and CT are open-drain outputs. Both outputs require a
10 kΩ pull-up resistor to V
powered up to V
before it can read INT and CT data.
DD
. The ADT7312 must be fully
DD
UNDERTEMPERATURE AND OVERTEMPERATURE DETECTION
The INT and CT pins have two undertemperature/overtemperature modes: comparator mode and interrupt mode. Interrupt
mode is the default power-on mode. The INT output becomes
active when the temperature is greater than the temperature
stored in the T
stored in the T
after an overtemperature or undertemperature event depends
on whether comparator mode or interrupt mode is selected.
Figure 18 illustrates the comparator and interrupt modes for
events exceeding the T
Figure 19 illustrates the comparator and interrupt modes for
events exceeding the T
setpoint register or less than the temperature
HIGH
setpoint register. How the INT pin reacts
LOW
limit with both pin polarity settings.
HIGH
limit with both pin polarity settings.
LOW
Comparator Mode
In comparator mode, the INT output returns to its inactive state
when the temperature falls below the T
above the T
LOW
+ T
HYST
limit.
HIGH
− T
HYST
limit or rises
Placing the ADT7312 into shutdown mode does not reset the
INT state in comparator mode.
Interrupt Mode
In interrupt mode, the INT output returns to its inactive state
when any ADT7312 register is read. When INT is reset, it becomes
active again only when the temperature is greater than the temperature stored in the T
temperature stored in the T
setpoint register or less than the
HIGH
setpoint register.
LOW
Placing the ADT7312 into shutdown mode resets the INT
output in interrupt mode.
Figure 18. INT Output Response to T
Overtemperature Events
HIGH
Rev. 0 | Page 20 of 24
Data Sheet ADT7312
TEMPERATURE
–13°C
–14°C
–15°C
–16°C
–17°C
–18°C
–19°C
–20°C
–21°C
–22°C
INT PIN
(COMPARATOR MODE)
POLARITY = ACTIVE LOW
INT PIN
(INTERRUPT MODE)
POLARITY = ACTIVE LOW
INT PIN
(INTERRUPT MODE)
POLARITY = ACTIVE HIGH
INT PIN
(COMPARATOR MODE)
POLARITY = ACTIVE HIGH
T
LOW
+ T
HYST
T
LOW
TIME
READ
READ READ
06791-021
CT OUTPUT
TEMPERATURE (°C)
138° 180°
V
DD
06791-019
REDUNDANT CRITICAL GENERATOR
The CT output is normally activated when the actual temperature exceeds the value stored in the T
value is 147°C + T
deactivated after the temperature exceeds 175°C, the ADT7312
incorporates a redundant standalone circuit (redundant critical
generator) to specifically control the CT output at temperatures
above 175°C.
This circuit incorporates hysteresis to ensure a safe working
temperature. Figure 20 shows the redundant critical generator
assuming control when the temperature reaches 180°C by activating the CT output; this circuit does not deactivate the CT
output until the temperature reaches 138°C. The redundant critical
generator is programmed in production to ensure that all parts
are triggered at the same temperatures (180°C and 138°C).
Figure 19. INT Output Response to T
setpoint register (default
CRIT
). To prevent the CT output from being
HYST
Rev. 0 | Page 21 of 24
Undertemperature Events
LOW
Figure 20. CT Output Response Using the Redundant Critical Generator
ADT7312 Data Sheet
0.1µF
ADT7312
TTL/CMOS
LOGIC
CIRCUITS
POWER
SUPPLY
06791-022
APPLICATIONS INFORMATION
THERMAL RESPONSE TIME
Thermal response is a function of the thermal mass of the
temperature sensor, but it is also heavily influenced by the
mass of the object that the IC is mounted to. For example, a
large PCB containing large amounts of copper tracking can
act as a large heat sink and slow the thermal response. For a
faster thermal response, it is recommended that the sensor
be mounted on a PCB that is as small as possible.
SUPPLY DECOUPLING
The ADT7312 must have a decoupling capacitor connected
between V
and GND; otherwise, incorrect temperature read-
DD
ings are obtained. A 0.1 µF decoupling capacitor, such as a high
frequency ceramic type, must be used and mounted as close as
possible to the V
pads of the ADT7312.
DD
If possible, the ADT7312 should be powered directly from the
system power supply (see Figure 21). This arrangement isolates
the analog section from the logic-switching transients. Even if
a separate power supply trace is not available, generous supply
bypassing reduces supply line induced errors. Local supply
bypassing consisting of a 0.1 µF ceramic capacitor is critical for
the temperature accuracy specifications to be achieved.
Figure 21. Use of Separate Traces to Reduce Power Supply Noise
POWERING FROM A SWITCHING REGULATOR
Precision analog devices such as the ADT7312 require a wellfiltered power source. If the ADT7312 is powered from a
switching regulator, noise can be generated above 50 kHz that
may affect the temperature accuracy specifications. To prevent
this, an RC filter should be used between the power supply and
the ADT7312 V
be carefully considered to ensure that the peak value of the supply
noise is less than 1 m V. The RC filter should be mounted as far
away as possible from the ADT7312 to ensure that the thermal
mass is kept as low as possible.
pins. The value of the components used should
DD
TEMPERATURE MONITORING
The ADT7312 is ideal for monitoring the thermal environment
of high temperature automotive applications. The ADT7312
measures and converts the temperature at the surface of its own
semiconductor chip.
When the ADT7312 is used to measure the temperature of a
nearby heat source, the thermal impedance between the heat
source and the ADT7312 must be considered. When the thermal
impedance is determined, the temperature of the heat source
can be inferred from the ADT7312 output. Most of the heat
transferred from the heat source to the thermal sensor on the
ADT7312 die is routed via the copper traces, the bond pads,
and GND.
Therefore, to measure the temperature of a heat source, it is
recommended that the thermal resistance between the GND
pads of the ADT7312 and the GND of the heat source be
reduced as much as possible.
QUICK GUIDE TO MEASURING TEMPERATURE
To measure temperature in continuous conversion mode
(default power-on mode), follow these steps.
1. After power-up, reset the serial interface (load 32
consecutive 1s on DIN). This step ensures that all
internal circuitry is correctly initialized.
2. Verify the setup by reading the device ID (Register
Address 0x03). It should read 0xC3.
3. After consistent consecutive readings are obtained from
the device ID register, read the following registers:
• Configuration register (Register Address 0x01)
• T
• T
• T
4. Compare the values in these registers to the default values
listed in Ta b l e 7 . If all the readings match Tab l e 7, the
interface is operational.
5. Write to the configuration register (Register Address 0x01)
to set the ADT7312 to the desired configuration. Read the
temperature value register (Register Address 0x02). It
should produce a valid temperature measurement.
setpoint register (Register Address 0x04)
CRIT
setpoint register (Register Address 0x06)
HIGH
setpoint register (Register Address 0x07)
LOW
Rev. 0 | Page 22 of 24
Data Sheet ADT7312
OUTLINE DIMENSIONS
2.350
0.092
1.950
CIRCUIT SIDE
(Activ eside)
Figure 22. 10-Pad Bare Die [CHIP]
Dimensions shown in millimeters
(C-10-1)
SIDE VIEW
01-14-2010-F
ORDERING GUIDE
1, 2
Model
Temperature Range3 Temperature Accuracy4 Package Description Package Option
ADT7312WCZ-PT7 −55°C to +175°C ±1.0°C Die in Pocket Tape C-10-1
EVAL-ADT7X10EBZ Evaluation Board
1
Z = RoHS Compliant Part.
2
W = Qualified for Automotive Applications.
3
Operating at extended temperatures over prolonged periods may shorten the lifetime performance of the part.
4
Maximum accuracy over the −55°C to +175°C temperature range (VDD = 2.7 V to 3.3 V).
AUTOMOTIVE PRODUCTS
The ADT7312W models are available with controlled manufacturing to support the quality and reliability requirements of automotive
applications. Note that these automotive models may have specifications that differ from the commercial models; therefore, designers
should review the Specifications section of this data sheet carefully. Only the automotive grade products shown are available for use in
automotive applications. Contact your local Analog Devices account representative for specific product ordering information and to
obtain the specific Automotive Reliability reports for these models.
Rev. 0 | Page 23 of 24
ADT7312 Data Sheet
©2012 Analog Devices, Inc. All rights reserved. Trademarks and
NOTES
registered trademarks are the property of their respective owners.
D06791-0-1/12(0)
Rev. 0 | Page 24 of 24
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