ADT7312 Automotive, ±1°C Accurate, 16-Bit, 175°C, Data Sheet

ADT7312 Automotive, ±1°C Accurate, 16-Bit, 175°C, Data Sheet
Automotive, ±1°C Accurate, 16-Bit, 175°C,
Digital SPI Temperature Sensor in Die Form
ADT7312
Data Sheet
FEATURES
GENERAL DESCRIPTION
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
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.
APPLICATIONS
PRODUCT HIGHLIGHTS
Automotive
High temperature monitoring
High temperature thermal protection
1.
2.
3.
4.
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.
Ease of use, no calibration or correction required.
Low power consumption.
Excellent long-term stability and reliability.
Qualified for automotive applications.
FUNCTIONAL BLOCK DIAGRAM
INTERNAL
REFERENCE
ADT7312
INTERNAL
OSCILLATOR
DOUT 2
DIN 3
SPI INTERFACE
SCLK 1
6
CT
5
INT
7
GND
8
GND
9
VDD
10
VDD
TCRIT
TEMPERATURE
SENSOR
Σ-∆
MODULATOR
THIGH
CS 4
FILTER
LOGIC
CONFIGURATION
REGISTER
TCRIT
REGISTER
TLOW
REGISTER
STATUS
REGISTER
TEMPERATURE
VALUE
REGISTER
THYST
REGISTER
THIGH
REGISTER
ID
REGISTER
06791-001
TLOW
Figure 1.
Rev. A
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©2012 Analog Devices, Inc. All rights reserved.
ADT7312
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1 Temperature Value Register ...................................................... 15 Applications ....................................................................................... 1 ID Register................................................................................... 15 General Description ......................................................................... 1 TCRIT Setpoint Register ............................................................... 15 Product Highlights ........................................................................... 1 THYST Setpoint Register............................................................... 16 Functional Block Diagram .............................................................. 1 THIGH Setpoint Register .............................................................. 16 Revision History ............................................................................... 2 TLOW Setpoint Register ............................................................... 16 Specifications..................................................................................... 3 Serial Interface ................................................................................ 17 SPI Timing Specifications ........................................................... 4 SPI Command Byte .................................................................... 17 Absolute Maximum Ratings............................................................ 5 Writing Data ............................................................................... 18 ESD Caution .................................................................................. 5 Reading Data............................................................................... 19 Pad Configuration and Function Descriptions ............................ 6 Interfacing to DSPs or Microcontrollers ................................. 19 Die Bond Pad Coordinates .............................................................. 7 Resetting the Serial Interface .................................................... 19 Typical Performance Characteristics ............................................. 8 INT and CT Outputs...................................................................... 20 Theory of Operation ........................................................................ 9 Undertemperature and Overtemperature Detection ............ 20 Circuit Description....................................................................... 9 Redundant Critical Generator .................................................. 21 Converter Architecture ................................................................ 9 Applications Information .............................................................. 22 Normal Mode (Continuous Conversion Mode) ...................... 9 Thermal Response Time ........................................................... 22 One-Shot Mode .......................................................................... 10 Supply Decoupling ..................................................................... 22 1 SPS Mode .................................................................................. 11 Powering from a Switching Regulator ..................................... 22 Shutdown Mode.......................................................................... 11 Temperature Monitoring ........................................................... 22 Fault Queue ................................................................................. 11 Quick Guide to Measuring Temperature ................................ 22 Temperature Data Format ......................................................... 12 Outline Dimensions ....................................................................... 23 Temperature Conversion Formulas ......................................... 12 Ordering Guide .......................................................................... 23 Registers ........................................................................................... 13 Automotive Products ................................................................. 23 Status Register ............................................................................. 13 Configuration Register .............................................................. 14 REVISION HISTORY
6/12—Rev. 0 to Rev. A
Changed High Output Leakage Current, IOH Maximum
Parameter from 5 μA to ±1 μA ....................................................... 3
1/12—Revision 0: Initial Version
Rev. A | Page 2 of 24
Data Sheet
ADT7312
SPECIFICATIONS
TA = −55°C to +175°C, VDD = 2.7 V to 5.5 V, unless otherwise noted.
Table 1.
Parameter
TEMPERATURE SENSOR AND ADC
Accuracy1
Min
ADC Resolution
Temperature Resolution
13-Bit
16-Bit
Temperature Conversion Time
Fast Temperature Conversion Time
1 SPS Conversion Time
Temperature Hysteresis
Repeatability2
DC PSRR
DIGITAL OUTPUTS (CT, INT)
High Output Leakage Current, IOH
Output Low Voltage, VOL
Output High Voltage, VOH
Output Capacitance, COUT
DIGITAL INPUTS (DIN, SCLK, CS)
Input Current, IIN
Input Low Voltage, VIL
Input High Voltage, VIH
Pin Capacitance, CIN
DIGITAL OUTPUT (DOUT)
Output High Voltage, VOH
Output Low Voltage, VOL
Output Capacitance, COUT
POWER REQUIREMENTS
Supply Voltage
Supply Current
Continuous Conversion Mode
1 SPS Mode
Shutdown Mode
Power Dissipation
Continuous Conversion Mode
1 SPS Mode
Shutdown Mode
1
2
Typ
Max
Unit
Test Conditions/Comments
±1.0
±1.1
±1.2
±1.5
13
°C
°C
°C
°C
Bits
16
Bits
TA = −55°C to +175°C, VDD = 2.7 V to 3.3 V
TA = −55°C to +175°C, VDD = 3.3 V to 3.6 V
TA = +150°C to +175°C, VDD = 4.5 V to 5.5 V
TA = −55°C to +175°C, VDD = 4.5 V to 5.5 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)
0.0625
0.0078
240
6
60
±0.002
±0.015
0.1
°C
°C
ms
ms
ms
°C
°C
°C/V
+0.1
μA
V
V
pF
±1
0.4
VIN = 0 V to VDD
10
μA
V
V
pF
0.4
50
V
V
pF
ISOURCE = ISINK = 200 μA
IOL = 200 μA
5.5
V
320
350
μA
μA
μA
μA
μA
μA
2
0.7 × VDD
VDD − 0.3
2.7
245
275
55
70
2.5
5.4
TA = 25°C
TA = 25°C
Open-drain outputs
CT and INT pins pulled up to 5.5 V
IOL = 3 mA at 5.5 V, IOL = 1 mA at 3.3 V
±1
0.4
0.7 × VDD
5
13-bit resolution (sign bit plus 12 bits)
16-bit resolution (sign bit plus 15 bits)
Continuous and one-shot conversion modes
First conversion on power-up only
1 SPS mode
40
50
880
200
9
μW
μW
μW
Accuracy includes lifetime drift.
Based on a floating average of 10 readings.
Rev. A | Page 3 of 24
Peak current while converting; SPI interface inactive
VDD = 3.6 V
VDD = 5.5 V
VDD = 3.6 V, TA = 25°C
VDD = 5.5 V, TA = 25°C
VDD = 3.6 V
VDD = 5.5 V
Power dissipated for VDD = 3.6 V, TA = 25°C
ADT7312
Data Sheet
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 VDD) and timed from a voltage level of 1.6 V.
Table 2.
Parameter 1, 2
t1
t2
t3
t4
t5
t6
t7 3
t8
t9
t10
Limit at TMIN, TMAX
0
100
100
30
25
5
60
80
10
80
0
0
60
80
10
Unit
ns min
ns min
ns min
ns min
ns min
ns min
ns max
ns max
ns min
ns max
ns min
ns min
ns max
ns max
ns min
Description
CS falling edge to SCLK active edge setup time
SCLK high pulse width
SCLK low pulse width
Data setup time prior to SCLK rising edge
Data hold time after SCLK rising edge
Data access time after SCLK falling edge
VDD = 4.5 V to 5.5 V
VDD = 2.7 V to 3.6 V
Bus relinquish time after CS inactive edge
SCLK inactive edge to CS rising edge hold time
CS falling edge to DOUT active time
VDD = 4.5 V to 5.5 V
VDD = 2.7 V to 3.6 V
SCLK inactive edge to DOUT low
Sample tested during initial release to ensure compliance.
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.
1
2
CS
t1
t2
2
1
SCLK
t8
t3
3
6
7
8
9
10
23
24
t4
t5
LSB
t6
t9
DOUT
MSB
t10
LSB
t7
Figure 2. Detailed SPI Timing Diagram
Rev. A | Page 4 of 24
06791-002
MSB
DIN
Data Sheet
ADT7312
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter
VDD to GND
DIN Input Voltage to GND
DOUT Output Voltage to GND
SCLK Input Voltage to GND
CS Input Voltage to GND
CT and INT Output Voltage to GND
ESD Rating (Human Body Model)
Operating Temperature Range
Storage Temperature Range
Maximum Junction Temperature, TJMAX
Rating
−0.3 V to +7 V
−0.3 V to VDD + 0.3 V
−0.3 V to VDD + 0.3 V
−0.3 V to VDD + 0.3 V
−0.3 V to VDD + 0.3 V
−0.3 V to VDD + 0.3 V
2.0 kV
−55°C to +175°C
−65°C to +175°C
175°C
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. A | Page 5 of 24
ADT7312
Data Sheet
PAD CONFIGURATION AND FUNCTION DESCRIPTIONS
1950µm
SCLK
VDD
VDD
DOUT
GND
GND
DIN
CT
CS
INT
06791-004
2350µm
Figure 3. Metallization Picture
Table 4. Pad Function Descriptions
Pad No.
1
2
3
Pad Name
SCLK
DOUT
DIN
4
5
CS
INT
6
CT
7
8
9
GND
GND
VDD
10
VDD
Description
Serial Clock Input. The serial clock is used to clock data into and out of any register of the device.
Serial Data Output. Data is clocked out on the falling edge of SCLK and is valid on the rising edge of SCLK.
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.
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.
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.
Analog Ground. This pad must be connected directly to Pad 8 (digital ground).
Digital Ground. This pad must be connected directly to Pad 7 (analog ground).
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.
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. A | Page 6 of 24
Data Sheet
ADT7312
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.
1
2
3
4
5
6
7
8
9
10
Pad Name
SCLK
DOUT
DIN
CS
INT
CT
GND
GND
VDD
VDD
X Coordinate (µm)
−838
−838
−838
−838
+838
+838
+838
+838
+838
+838
Y Coordinate (µm)
+1020
+831
−863
−1011
−1011
−863
+508
+702
+857
+1008
Rev. A | Page 7 of 24
ADT7312
Data Sheet
TYPICAL PERFORMANCE CHARACTERISTICS
30
1.0
VDD
VDD
VDD
VDD
VDD
VDD
0.8
0.6
SHUTDOWN IDD (µA)
TEMPERATURE ERROR (ºC)
25
0.4
0.2
0
–0.2
20
= 2.7V
= 3.0V
= 3.6V
= 4.5V
= 5.0V
= 5.5V
15
10
–0.4
5
30 50 70 90 110 130 150 170 190
TEMPERATURE (ºC)
0
–60 –40 –20
06791-005
–0.8
–70 –50 –30 –10 10
Figure 4. Temperature Accuracy at 3 V
0
20 40 60 80 100 120 140 160 180
TEMPERATURE (°C)
06791-008
–0.6
Figure 7. Shutdown Current vs. Temperature
300
1.5
1.0
200
0.5
IDD (µA)
150
0
100
1SPS
–0.5
50
0
2.5
4.0
4.5
5.0
5.5
6.0
Figure 8. Operating Supply Current vs. Supply Voltage
6
350
5V CONTINUOUS CONVERSION
250
5
SHUTDOWN IDD (µA)
3V CONTINUOUS CONVERSION
200
150
5V 1SPS
100
3V 1SPS
50
0
–60 –40 –20
0
20 40 60 80 100 120 140 160 180
TEMPERATURE (°C)
4
3
2
1
06791-007
IDD (µA)
3.5
SUPPLY VOLTAGE (V)
Figure 5. Temperature Accuracy at 5 V
300
3.0
06791-009
30 50 70 90 110 130 150 170 190
TEMPERATURE (ºC)
06791-006
–1.0
–70 –50 –30 –10 10
Figure 6. Operating Supply Current vs. Temperature
0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
SUPPLY VOLTAGE (V)
Figure 9. Shutdown Current vs. Supply Voltage
Rev. A | Page 8 of 24
6.0
06791-010
TEMPERATURE ERROR (ºC)
CONTINUOUS CONVERSION
250
Data Sheet
ADT7312
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.
Σ-Δ MODULATOR
INTEGRATOR
COMPARATOR
VOLTAGE
REFERENCE
The ADT7312 can be configured to operate in any one of the
following operating modes:
•
•
•
•
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 TCRIT setpoint register),
a high temperature limit (stored in the 16-bit THIGH setpoint
register), and a low temperature limit (stored in the 16-bit TLOW
setpoint register). If the measured value exceeds the THIGH or
TLOW limit, the INT pin is activated; if the measured value
exceeds the TCRIT limit, the CT pin is activated. The polarity of
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.
1-BIT
DAC
LPF DIGITAL
FILTER
TEMPERATURE
VALUE
REGISTER
13/16 BITS
06791-011
1 BIT
CLOCK
GENERATOR
Normal mode (continuous conversion mode)
One-shot mode
1 SPS mode
Shutdown mode
Figure 10. Σ-∆ Modulator
Rev. A | Page 9 of 24
ADT7312
Data Sheet
ONE-SHOT MODE
CT and INT Operation in 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.
Figure 12 illustrates the operation of the CT pin in one-shot
mode when the TCRIT overtemperature limit is exceeded. Note
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.)
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.
If the INT pin is configured for comparator mode and the
temperature falls below the THIGH − THYST value or exceeds the
TLOW + THYST value, a write to the operation mode bits of the
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 TCRIT − THYST value, a write to the
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.
CS
DIN
0x08
0x20
WAIT 240ms MINIMUM
FOR CONVERSION TO FINISH
DATA
06791-012
DOUT
SCLK
Figure 11. Typical SPI One-Shot Write to Configuration Register Followed by a Read from the Temperature Value Register
Rev. A | Page 10 of 24
Data Sheet
ADT7312
TEMPERATURE
149°C
148°C
TCRIT
147°C
146°C
145°C
144°C
143°C
TCRIT – THYST
142°C
141°C
140°C
139°C
CT PIN
POLARITY =
ACTIVE LOW
CT PIN
POLARITY =
ACTIVE HIGH
TIME
*AFTER WRITING TO THE CONFIGURATION REGISTER TO START A ONE-SHOT
CONVERSION, THE CONVERSION TIME IS 240ms. THEREFORE, IT TAKES AT
LEAST 240ms AFTER THE WRITE TO THE CONFIGURATION REGISTER
BEFORE THE CT PIN BECOMES ACTIVE.
06791-013
WRITE 01 TO
WRITE 01 TO
WRITE 01 TO
BITS[6:5] OF
BITS[6:5] OF
BITS[6:5] OF
CONFIGURATION CONFIGURATION CONFIGURATION
REGISTER*
REGISTER*
REGISTER*
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. A | Page 11 of 24
ADT7312
Data Sheet
TEMPERATURE DATA FORMAT
TEMPERATURE CONVERSION FORMULAS
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 TCRIT
setpoint register and the THIGH setpoint register. The temperature
measurement result is also compared with the low temperature
limit stored in the TLOW setpoint register.
16-Bit Temperature Data Format
Temperature data in the temperature value register, the TCRIT
setpoint register, the THIGH setpoint register, and the TLOW setpoint
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 TCRIT, THIGH, and TLOW. Table 6 shows
the 13-bit temperature data format without Bits[2:0].
Table 6. 13-Bit Temperature Data Format
Temperature
−55°C
−50°C
−25°C
−0.0625°C
0°C
+0.0625°C
+25°C
+50°C
+125°C
+150°C
+175°C
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
Digital Output (Bits[D15:D3])
Binary
Hex
1 1100 1001 0000
0x1C90
1 1100 1110 0000
0x1CE0
1 1110 0111 0000
0x1E70
1 1111 1111 1111
0x1FFF
0 0000 0000 0000
0x0000
0 0000 0000 0001
0x0001
0 0001 1001 0000
0x0190
0 0011 0010 0000
0x0320
0 0111 1101 0000
0x07D0
0 1001 0110 0000
0x0960
0 1010 1111 0000
0x0AF0
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
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.
where the MSB is removed from the ADC code.
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 Table 6.
Rev. A | Page 12 of 24
Data Sheet
ADT7312
REGISTERS
The ADT7312 contains eight registers.
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.
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
0x00
0x01
0x02
0x03
0x04
0x05
0x06
0x07
Register Name
Status
Configuration
Temperature value
ID
TCRIT setpoint
THYST setpoint
THIGH setpoint
TLOW setpoint
Power-On Default
0x80
0x00
0x0000
0xC3
0x4980 (147°C)
0x05 (5°C)
0x2000 (64°C)
0x0500 (10°C)
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 RDY
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,
the RDY bit is reset after a write to the operation mode bits of
the configuration register (Register Address 0x01, Bits[6:5]).
Table 8. Status Register (Register Address 0x00)
Bits
7
Default Value
1
Type
R
Name
RDY
6
0
R
TCRIT
5
0
R
THIGH
4
0
R
TLOW
[3:0]
0000
R
Unused
Description
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]).
This bit is set to 1 when the temperature exceeds the TCRIT temperature limit. This bit
is cleared to 0 when the status register is read or when the measured temperature
falls below the limit (TCRIT − THYST) set in the TCRIT setpoint and THYST setpoint registers.
This bit is set to 1 when the temperature exceeds the THIGH temperature limit. This bit
is cleared to 0 when the status register is read or when the measured temperature
falls below the limit (THIGH − THYST) set in the THIGH setpoint and THYST setpoint registers.
This bit is set to 1 when the temperature goes below the TLOW temperature limit. This
bit is cleared to 0 when the status register is read or when the measured temperature
rises above the limit (TLOW + THYST) set in the TLOW setpoint and THYST registers.
Reads back 0000.
Rev. A | 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
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.
Table 9. Configuration Register (Register Address 0x01)
Bits
7
Default Value
0
Type
R/W
Name
Resolution
[6:5]
00
R/W
Operation mode
4
0
R/W
INT/CT mode
3
0
R/W
INT pin polarity
2
0
R/W
CT pin polarity
[1:0]
00
R/W
Fault queue
Description
This bit sets the resolution of the ADC when converting.
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.
These two bits set the operational mode for the ADT7312.
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.
This bit selects comparator mode or interrupt mode.
0 = interrupt mode.
1 = comparator mode.
This bit selects the output polarity of the INT pin.
0 = active low.
1 = active high.
This bit selects the output polarity of the CT pin.
0 = active low.
1 = active high.
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.
Rev. A | Page 14 of 24
Data Sheet
ADT7312
TEMPERATURE VALUE REGISTER
ID 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.
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].
When the ADC is configured to convert the temperature to
a 13-bit digital value, Bits[2:0] are event alarm flags for TCRIT,
THIGH, and TLOW. When the ADC is configured to convert the
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).
TCRIT SETPOINT REGISTER
The 16-bit, read/write TCRIT setpoint register (Register
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 TCRIT setpoint is +147°C.
Table 10. Temperature Value Register (Register Address 0x02)
Bits
15
Default Value
0
Type
R
Name
Sign
[14:8]
[7:3]
2
0000000
00000
0
R
R
R
Temp
Temp
TCRIT flag/LSB 2
1
0
R
THIGH flag/LSB 1
0
0
R
TLOW flag/LSB 0
Description
Sign bit. Indicates whether the temperature value is negative or positive
(0 = positive, 1 = negative).
Temperature value (Bits[14:8]) in twos complement format.
Temperature value (Bits[7:3]) in twos complement format.
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
TCRIT, 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 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 THIGH,
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
TLOW, 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 0 of the 15-bit temperature value.
Table 11. ID Register (Register Address 0x03)
Bits
[7:3]
[2:0]
Default Value
11000
011
Type
R
R
Name
Manufacturer ID
Revision ID
Description
Contains the manufacturer identification number.
Contains the silicon revision identification number.
Table 12. TCRIT Setpoint Register (Register Address 0x04)
Bits
[15:0]
Default Value
0x4980
Type
R/W
Name
TCRIT
Description
16-bit critical overtemperature limit, stored in twos complement format. The
default setting is +147°C.
Rev. A | Page 15 of 24
ADT7312
Data Sheet
THYST SETPOINT REGISTER
The 8-bit, read/write THYST setpoint register (Register Address 0x05)
stores the temperature hysteresis value for the THIGH, TLOW, and
TCRIT temperature limits. The temperature hysteresis value is
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 THIGH and TCRIT values and is added to the TLOW value.
The default setting for the THYST setpoint is +5°C.
THIGH SETPOINT REGISTER
The 16-bit, read/write THIGH setpoint register (Register
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 THIGH setpoint is +64°C.
TLOW SETPOINT REGISTER
The 16-bit, read/write TLOW setpoint register (Register
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 TLOW setpoint is +10°C.
Table 13. THYST Setpoint Register (Register Address 0x05)
Bits
[7:4]
Default Value
0000
Type
R/W
Name
Unused
Description
Not used.
[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.
Table 14. THIGH Setpoint Register (Register Address 0x06)
Bits
[15:0]
Default Value
0x2000
Type
R/W
Name
THIGH
Description
16-bit overtemperature limit, stored in twos complement format. The default
setting is +64°C.
Table 15. TLOW Setpoint Register (Register Address 0x07)
Bits
[15:0]
Default Value
0x0500
Type
R/W
Name
TLOW
Description
16-bit undertemperature limit, stored in twos complement format. The default
setting is +10°C.
Rev. A | Page 16 of 24
Data Sheet
ADT7312
SERIAL INTERFACE
PULL-UP
TO VDD
VDD
10kΩ
VDD
ADT7312
SCLK
DOUT
DIN
CS
GND
CT
INT
06791-023
MICROCONTROLLER
10kΩ
0.1µF
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 (CS) enables or disables
the ADT7312. CS is required for correct operation of the serial
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. Table 16 shows the command byte.
Table 16. Command Byte
C7
0
C6
R/W
C5
C4
C3
Register address
C2
0
C1
0
C0
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. A | Page 17 of 24
ADT7312
Data Sheet
Figure 14 shows a write to an 8-bit register, and Figure 15 shows
a write to a 16-bit register.
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 high.
The master must begin a new write transaction on the bus, for
every register write. Only one register is written to per bus
transaction.
CS
1
2
3
4
5
6
7
8
9
10
11
DIN
R/W
C7
C6
REGISTER ADDR
0
0
0
C4
C2
C1
C0
C5
C3
13
14
15
16
8-BIT DATA
8-BIT COMMAND BYTE
0
12
D7
D6
D5
D4
D3
D2
D1
06791-015
SCLK
D0
Figure 14. Writing to an 8-Bit Register
CS
1
2
3
4
5
6
7
8
9
10
11
12
13
14
DIN
R/W
REGISTER ADDR
C7
C6
C5
C4
C3
16
17
22
23
24
16-BIT DATA
8-BIT COMMAND BYTE
0
15
0
0
0
C2
C1
C0
D15
D14
D13
D12
D11
D10
Figure 15. Writing to a 16-Bit Register
Rev. A | Page 18 of 24
D9
D8
D7
D2
D1
D0
06791-016
SCLK
Data Sheet
ADT7312
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.
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.
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.
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 CS because CS
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
SCLK
2
1
4
3
5
7
6
9
8
11
10
12
13
14
16
15
8-BIT COMMAND BYTE
DIN
0
R/W
C7
C6
REGISTER ADDR
C5
C3
C4
0
0
0
C2
C1
C0
D7
D6
D5
D4
D3
D2
D1
06791-017
8-BIT DATA
DOUT
D0
Figure 16. Reading from an 8-Bit Register
CS
SCLK
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
22
23
24
8-BIT COMMAND BYTE
DIN
0
R/W
C7
C6
REGISTER ADDR
0
0
0
C4
C2
C1
C0
C5
C3
DOUT
D15
D14
D13
D12
D11
D10
Figure 17. Reading from a 16-Bit Register
Rev. A | Page 19 of 24
D9
D8
D7
D2
D1
D0
06791-018
16-BIT DATA
ADT7312
Data Sheet
INT AND CT OUTPUTS
Comparator Mode
INT and CT are open-drain outputs. Both outputs require a
10 kΩ pull-up resistor to VDD. The ADT7312 must be fully
powered up to VDD before it can read INT and CT data.
In comparator mode, the INT output returns to its inactive state
when the temperature falls below the THIGH − THYST limit or rises
above the TLOW + THYST limit.
UNDERTEMPERATURE AND OVERTEMPERATURE
DETECTION
Placing the ADT7312 into shutdown mode does not reset the
INT state in comparator mode.
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 THIGH setpoint register or less than the temperature
stored in the TLOW setpoint register. How the INT pin reacts
after an overtemperature or undertemperature event depends
on whether comparator mode or interrupt mode is selected.
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 THIGH setpoint register or less than the
temperature stored in the TLOW setpoint register.
Placing the ADT7312 into shutdown mode resets the INT
output in interrupt mode.
Figure 18 illustrates the comparator and interrupt modes for
events exceeding the THIGH limit with both pin polarity settings.
Figure 19 illustrates the comparator and interrupt modes for
events exceeding the TLOW limit with both pin polarity settings.
TEMPERATURE
82°C
81°C
THIGH
80°C
79°C
78°C
77°C
76°C
THIGH – THYST
75°C
74°C
73°C
INT PIN
(COMPARATOR MODE)
POLARITY = ACTIVE LOW
INT PIN
(INTERRUPT MODE)
POLARITY = ACTIVE LOW
INT PIN
(COMPARATOR MODE)
POLARITY = ACTIVE HIGH
TIME
READ
READ
READ
Figure 18. INT Output Response to THIGH Overtemperature Events
Rev. A | Page 20 of 24
06791-020
INT PIN
(INTERRUPT MODE)
POLARITY = ACTIVE HIGH
Data Sheet
ADT7312
TEMPERATURE
–13°C
–14°C
TLOW + THYST
–15°C
–16°C
–17°C
–18°C
–19°C
TLOW
–20°C
–21°C
–22°C
INT PIN
(COMPARATOR MODE)
POLARITY = ACTIVE LOW
INT PIN
(INTERRUPT MODE)
POLARITY = ACTIVE LOW
INT PIN
(COMPARATOR MODE)
POLARITY = ACTIVE HIGH
TIME
READ
READ
READ
06791-021
INT PIN
(INTERRUPT MODE)
POLARITY = ACTIVE HIGH
Figure 19. INT Output Response to TLOW Undertemperature Events
REDUNDANT CRITICAL GENERATOR
The CT output is normally activated when the actual temperature exceeds the value stored in the TCRIT setpoint register (default
value is 147°C + THYST). To prevent the CT output from being
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.
CT OUTPUT
138°
180°
TEMPERATURE (°C)
06791-019
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).
VDD
Figure 20. CT Output Response Using the Redundant Critical Generator
Rev. A | Page 21 of 24
ADT7312
Data Sheet
APPLICATIONS INFORMATION
THERMAL RESPONSE TIME
TEMPERATURE MONITORING
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.
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.
SUPPLY DECOUPLING
The ADT7312 must have a decoupling capacitor connected
between VDD and GND; otherwise, incorrect temperature readings 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 VDD pads of the ADT7312.
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.
TTL/CMOS
LOGIC
CIRCUITS
0.1µF
ADT7312
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.
2.
POWER
SUPPLY
06791-022
3.
•
•
•
•
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 VDD pins. The value of the components used should
be carefully considered to ensure that the peak value of the supply
noise is less than 1 mV. 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.
After power-up, reset the serial interface (load 32
consecutive 1s on DIN). This step ensures that all
internal circuitry is correctly initialized.
Verify the setup by reading the device ID (Register
Address 0x03). It should read 0xC3.
After consistent consecutive readings are obtained from
the device ID register, read the following registers:
4.
5.
Rev. A | Page 22 of 24
Configuration register (Register Address 0x01)
TCRIT setpoint register (Register Address 0x04)
THIGH setpoint register (Register Address 0x06)
TLOW setpoint register (Register Address 0x07)
Compare the values in these registers to the default values
listed in Table 7. If all the readings match Table 7, the
interface is operational.
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.
Data Sheet
ADT7312
OUTLINE DIMENSIONS
2.350
0.092
CIRCUIT SIDE
(Active side)
SIDE VIEW
01-14-2010-F
1.950
Figure 22. 10-Pad Bare Die [CHIP]
(C-10-1)
Dimensions shown in millimeters
ORDERING GUIDE
Model1, 2
ADT7312WCZ-PT7
EVAL-ADT7X10EBZ
Temperature Range3
−55°C to +175°C
Temperature Accuracy4
±1.0°C
Package Description
Die in Pocket Tape
Evaluation Board
Package Option
C-10-1
1
Z = RoHS Compliant Part.
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).
2
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. A | Page 23 of 24
ADT7312
Data Sheet
NOTES
©2012 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D06791-0-6/12(A)
Rev. A | Page 24 of 24
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