ANALOG DEVICES ADT7310 Service Manual

Digital SPI Temperature Sensor

ADT7310

Rev. A

ed by Analog Devices is believed to be accurate and reliable. However, no

Trademarks and registered trademarks are the property of their respective owners.

Fax: [phone] ©2009–2011 Analog Devices, Inc. All rights reserved.

INTERNAL

REFERENCE

8

7

TEMPERATURE

SENSOR

T

HIGH

T

CRIT

T

LOW

INTERNAL

OSCILLATOR

FILTER

LOGIC

Σ-Δ

MODULATOR

V

DD

GND

6

5

CT

INT

3

4

1

2

ADT7310

CS

SPI INT E RFACE

TEMPERATURE

VALUE

REGISTER

CONFIGURATION

AND STATUS

REGISTERS

T

LOW

REGISTER

T

CRIT

REGISTER

T

HYST

REGISTER

T

HIGH

REGISTER

SCLK

DOUT

DIN

07789-001

Data Sheet

FEATURES

High performance

Temperature accuracy

±0.5°C from −40°C to +105°C (2.7 V to 3.6 V)

±0.4°C from −40°C to +105°C (3.0 V)
16-bit temperature resolution: 0.0078°C
Fast first temperature conversion on power-up of 6 ms

Easy implementation

No temperature calibration/correction required by user
No linearity correction required

Low power

Power saving 1 sample per second (SPS) mode
700 µW typical at 3.3 V in normal mode
7 µW typical at 3.3 V in shutdown mode

Wide operating ranges

Temperature range: −55°C to +150°C
Voltage range: 2.7 V to 5.5 V

Programmable interrupts

Critical overtemperature interrupt
Overtemperature/undertemperature interrupt

SPI-compatible interface
8-lead narrow SOIC RoHS-compliant package

APPLICATIONS

Medical equipment
Environmental control systems
Computer thermal monitoring

±0.5°C Accurate, 16-Bit

Thermal protection
Industrial process control
Power system monitors
Hand-held applications

GENERAL DESCRIPTION

The ADT7310 is a high accuracy digital temperature sensor
in a narrow SOIC package. It contains a band gap temperature
reference and a 13-bit ADC to monitor and digitize the
temperature to a 0.0625°C resolution. The ADC resolution,
by default, is set to 13 bits (0.0625 °C). This can be changed
to 16 bits (0.0078 °C) by setting Bit 7 in the configuration
register (Register Address 0x01).

The ADT7310 is guaranteed to operate over supply voltages from

2.7 V to 5.5 V. Operating at 3.3 V, the average supply current is
typically 210 μA. The ADT7310 has a shutdown mode that
powers down the device and offers a shutdown current of
typically 2 μA. The ADT7310 is rated for operation over the

−55°C to +150°C temperature range.

The CT pin is an open-drain output that becomes active when
the temperature exceeds a programmable critical temperature
limit. The 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 and CT
pins can operate in either comparator or interrupt mode.

Information furnish
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

FUNCTIONAL BLOCK DIAGRAM

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone]

Figure 1.

www.analog.com

ADT7310 Data Sheet

TABLE OF CONTENTS

Features .............................................................................................. 1

Status Register ............................................................................. 14

Applications ....................................................................................... 1

General Description ......................................................................... 1

Functional Block Diagram .............................................................. 1

Revision History ............................................................................... 2

Specifications ..................................................................................... 3

SPI Timing Specifications ........................................................... 4

Absolute Maximum Ratings ............................................................ 5

ESD Caution .................................................................................. 5

Pin Configuration and Function Descriptions ............................. 6

Typical Performance Characteristics ............................................. 7

Theory of Operation ........................................................................ 9

Circuit Information ...................................................................... 9

Converter Details.......................................................................... 9

Temperature Measurement ......................................................... 9

One-Shot Mode .......................................................................... 10

Configuration Register .............................................................. 15

Temperature Value Register ...................................................... 16

ID Register................................................................................... 16

T

Setpoint Register ............................................................... 16

CRIT

T

Setpoint Register ............................................................... 17

HYST

T

Setpoint Register .............................................................. 17

HIGH

T

Setpoint Register ............................................................... 17

LOW

Serial Interface ................................................................................ 18

SPI Command Byte .................................................................... 18

Writing Data ............................................................................... 19

Reading Data ............................................................................... 20

Interfacing to DSPs or Microcontrollers ................................. 20

Serial Interface Reset .................................................................. 20

INT and CT Outputs ...................................................................... 21

Undertemperature and Overtemperature Detection ............ 21

1 SPS Mode .................................................................................. 10

Continuous Read Mode ............................................................. 12

Shutdown ..................................................................................... 12

Fault Queue ................................................................................. 12

Temperature Data Format ......................................................... 13

Temperature Conversion Formulas ......................................... 13

Registers ........................................................................................... 14

REVISION HISTORY

12/11—Rev. 0 to Rev. A

Changes to Features Section............................................................ 1

Changes to Table 1 ............................................................................ 3

Changes to Figure 6 and Figure 9 ................................................... 7

Changes to Figure 11 ........................................................................ 8

Changes to One-Shot Mode Section and 1 SPS Mode

Section .............................................................................................. 10

Changes to Shutdown Section and Figure 16 ............................. 12

Applications Information .............................................................. 23

Thermal Response Time ........................................................... 23

Supply Decoupling ..................................................................... 23

Temperature Monitoring ........................................................... 23

Outline Dimensions ....................................................................... 24

Ordering Guide .......................................................................... 24

Changes to Table 7 .......................................................................... 14

Changes to Table 8 .......................................................................... 15

Changes to Table 9 .......................................................................... 16

Changes to Table 12, Table 13, and Table 14 ............................... 17

Changes to Ordering Guide .......................................................... 24

4/09—Revision 0: Initial Version

Rev. A | Page 2 of 24

Data Sheet ADT7310

±0.5

°C

TA = −40°C to +105°C, VDD = 2.7 V to 3.6 V

±0.7

°C

TA = −55°C to +150°C, VDD = 2.7 V to 3.6 V

Twos complement temperature value of sign bit plus 12 ADC bits

Output High Voltage, VOH

0.7 × VDD

V

SPECIFICATIONS

TA = −55°C to +150°C; VDD = 2.7 V to 5.5 V; unless otherwise noted.

Table 1.

Parameter Min Typ Max Unit Test Conditions/Comments

TEMPERATURE SENSOR AND ADC

Accuracy1 −0.05 ±0.42 °C TA = −40°C to +105°C, VDD = 3.0 V
±0.44 °C TA = −40°C to +105°C, VDD = 2.7 V to 3.3 V
±0.5 °C TA = −55°C to +125°C, VDD = 3.0 V

±0.8 °C TA = −40°C to +105°C, VDD = 4.5 V to 5.5 V
±1.0 °C TA = −55°C to +150°C, VDD = 2.7 V to 5.5 V
ADC Resolution 13 Bits

16 Bits

Temperature Resolution

13-Bit 0.0625 °C 13-bit resolution (sign + 12-bit)

16-Bit 0.0078 °C 16-bit resolution (sign + 15-bit)
Temperature Conversion Time 240 ms Continuous conversion and one-shot conversion mode
Fast Temperature Conversion Time 6 ms First conversion on power-up only
1 SPS Conversion Time 60 ms Conversion time for 1 SPS mode
Temperature Hysteresis ±0.002 °C Temperature cycle = 25°C to 125°C, and back to 25°C
Repeatability3 ±0.015 °C TA = 25°C

DC PSRR 0.1 °C/V TA = 25°C
DIGITAL OUTPUTS (OPEN DRAIN)

High Output Leakage Current, IOH 0.1 5 µA CT and INT pins pulled up to 5.5 V
Output High Current 1 mA VOH = 5 .5V
Output Low Voltage, VOL 0.4 V IOL = 2 mA @ 5.5 V, IOL = 1 mA @ 3.3 V

(power-up default resolution)
Twos complement temperature value of sign bit plus 15 ADC bits

(Bit 7 = 1 in the configuration register)

Output Capacitance, C

OUT

3 pF

DIGITAL INPUTS

Input Current ±1 µA VIN = 0 V to VDD
Input Low Voltage, VIL 0.4 V
Input High Voltage, VIH 0.7 × VDD V
Pin Capacitance 5 10 pF

DIGITAL OUTPUT (DOUT)

Output High Voltage, VOH VOH − 0.3 V I
Output Low Voltage, V
Output Capacitance, C

OL

50 pF

OUT

0.4 V IOL = 200 µA

SOUR CE

= I

= 200 µA

SINK

POWER REQUIREMENTS

Supply Voltage 2.7 5.5 V
Supply Current

At 3.3 V 210 250 µA Peak current while converting, SPI interface inactive

At 5.5 V 250 300 µA Peak current while converting, SPI interface inactive
1 SPS Current

At 3.3V 46 µA VDD = 3.3 V, 1 SPS mode, TA = 25°C

At 5.5V 65 µA VDD = 5.5 V, 1 SPS mode, TA = 25°C
Shutdown Current

At 3.3 V 2.0 15 µA Supply current in shutdown mode

At 5.5 V 5.2 25 µA Supply current in shutdown mode
Power Dissipation Normal Mode 700 µW VDD = 3.3 V, normal mode at 25°C
Power Dissipation 1 SPS 150 µW Power dissipated for VDD = 3.3 V, TA = 25°C

1

Accuracy includes lifetime drift.

2

The equivalent 3 σ limits are ±0.33°C. This 3 σ specification is provided to enable comparison with other vendors who use these limits.

3

Based on a floating average of 10 readings.

Rev. A | Page 3 of 24

ADT7310 Data Sheet

SPI TIMING SPECIFICATIONS

TA = −55°C to +150°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

(B Version) Unit Conditions/Comments

MAX

falling edge to SCLK active edge setup time3

CS
t2 100 ns min SCLK high pulse width
t3 100 ns min SCLK low pulse width
t4 30 ns min Data valid to SCLK edge setup time
t5 25 ns min Data valid to SCLK edge hold time
t6 0 ns min SCLK active edge to data valid delay3
60 ns max VDD = 4.5 V to 5.5 V
80 ns max VDD = 2.7 V to 3.6 V

4

t

10 ns min

7

Bus relinquish time after CS

inactive edge
80 ns max
t8 0 ns min
t9 0 ns min

rising edge to SCLK edge hold time

CS

falling edge to DOUT active time

CS
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 high

1

Sample tested during initial release to ensure compliance. All input signals are specified with tR = tF = 5 ns (10% to 90% of VDD) and timed from a voltage level of 1.6 V.

2

See Figure 2.

3

SCLK active edge is falling edge of SCLK.

4

This means that the times quoted in the timing characteristics are the true bus relinquish times of the part and, as such, are independent of external bus loading

capacitances.

CS

t

1

t

SCLK

DIN

DOUT

2

1

t

4

t

5

MSB LSB

t

9

t

3

23

7

8

12

t

6

MSB

t

8

7

8

t

10

t

7

LSB

07789-002

Figure 2. Detailed SPI Timing Diagram

I

(1.6mA WITH VDD = 5V,

SINK

100µA WITH V

TO

OUTPUT

PIN

10pF

I

SOURCE

100µA WITH V

Figure 3. Load Circuit for Timing Characterization

= 3V)

DD

1.6V

(200µA WIT H VDD=5V,

= 3V)

DD

07789-004

Rev. A | Page 4 of 24

Data Sheet ADT7310

Operating Temperature Range

–55°C to +150°C

Thermal Impedance3

Time at Peak Temperature

20 sec to 40 sec

TEMPERATURE (°C)

MAXIMUM POWER DISSIPATION (W)

1.2

0.8

1.0

0.6

0.2

0.4

0

–55

–50

–40

–30

–20

–10

0

102030405060708090

100

110

120

130

140

150

MAX PD = 3.4mW AT 150°C

07789-003

ABSOLUTE MAXIMUM RATINGS

Table 3.

Parameter Rating

VDD to GND –0.3 V to +7 V
DIN Input Voltage to GND –0.3 V to VDD + 0.3 V
DOUT Voltage to GND –0.3 V to VDD + 0.3 V
SCLK Input Voltage to GND –0.3 V to VDD + 0.3 V
CS Input Voltage to GND –0.3 V to VDD + 0.3 V
CT and INT Output Voltage to GND –0.3 V to VDD + 0.3 V
ESD Rating (Human Body Model) 2.0 kV

Storage Temperature Range –65°C to +160°C
Maximum Junction Temperature, T

150°C

JMAX

8-Lead SOIC-N (R-8)

Power Dissipation1 W

MAX

= (T

JMAX

− T

2

A

θJA, Junction-to-Ambient (Still Air) 121°C/W
θJC, Junction-to-Case 56°C/W

IR Reflow Soldering 220°C

Peak Temperature (RoHS-

260°C (0°C)

Compliant Package)

)/θJA

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.

Ramp-Up Rate 3°C/sec maximum
Ramp-Down Rate –6°C/sec maximum
Time from 25°C to Peak Temperature 8 minutes maximum

1

Values relate to package being used on a standard 2-layer PCB. This gives a

worst-case θ
vs. ambient temperature (T

2

TA = ambient temperature.

3

Junction-to-case resistance is applicable to components featuring a

preferential flow direction, for example, components mounted on a heat
sink. Junction-to-ambient is more useful for air-cooled, PCB-mounted
components.

and θJC. See Figure 4 for a plot of maximum power dissipation

JA

).

A

Figure 4. SOIC_N Maximum Power Dissipation vs. Temperature

ESD CAUTION

Rev. A | Page 5 of 24

ADT7310 Data Sheet

SCLK

1

DOUT

2

DIN

3

CS

4

V

DD

8

GND

7

CT

6

INT

5

ADT7310

TOP VIEW

(Not to Scale)

07789-005

5

INT

Overtemperature and Undertemperature Indicator. Logic output. Power-up default setting is as an active low

8

VDD

Positive Supply Voltage (2.7 V to 5.5 V). The supply should be decoupled with a 0.1 µF ceramic capacitor to

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

Figure 5. Pin Configuration

Table 4. Pin Function Descriptions

Pin No. Mnemonic Description

1 SCLK Serial Clock Input. The serial clock is used to clock in and clock out data to and from any register of the ADT7310.
2 DOUT Serial Data Output. Data is clocked out on the SCLK falling edge and is valid on the SCLK rising edge.
3 DIN Serial Data Input. Serial data to be loaded to the part’s control registers is provided on this input. Data is clocked

into the registers on the rising edge of SCLK.

4

CS

Chip Select Input. The device is selected when this input is low. The device is disabled when this pin is high.

comparator interrupt. Open-drain configuration. A pull-up resistor is required, typically 10 kΩ.

6 CT Critical Overtemperature Indicator. Logic output. Power-up default polarity is active low. Open-drain

configuration. A pull-up resistor is required, typically 10 kΩ.

7 GND Analog and Digital Ground.

ground.

Rev. A | Page 6 of 24

Data Sheet ADT7310

TEMPERATURE ERROR (°C)

1.0

07789-024

–1.0

–0.8

–0.6

–0.4

–0.2

0

0.2

0.4

0.6

0.8

1.0

–60 –40 –20 0 20 40 60 80 100 120 140 160

TEMPERATURE ERROR (°C)

TEMPERATURE (°C)

MAX ACCURACY LIM ITS

MAX ACCURACY LIM ITS

0

0.05

0.10

0.15

0.20

0.25

0.30

–100 –50 0 50 100 150 200

I

DD

(mA)

TEMPERA

TURE (°C)

3.0V 1SPS

5.5V 1SPS

5.5V CONTI NUOUS
CONVERSION

3.0V CONTI NUOUS
CONVERSION

07789-007

07789-025

3.6V

SHUTDOWN I

DD

(µA)

TEMPERATURE (°C)

0

5

10

15

20

25

30

–100 –50 0 50 100 150 200

3.3V

3.0V

2.7V

4.5V

5.0V

5.5V

TYPICAL PERFORMANCE CHARACTERISTICS

0.8

0.6

0.4

0.2

0

–0.2

–0.4

–0.6

–0.8

–1.0

–60 –40 –20 0 20 40 60 80 100 120 140 160

MAX ACCURACY LIM ITS

MAX ACCURACY LIM ITS

TEMPERATURE (°C)

Figure 6. Temperature Accuracy at 3 V

07789-006

Figure 8. Operating Supply Current vs. Temperature

Figure 7. Temperature Accuracy at 5 V

Figure 9. Shutdown Current vs. Temperature

Rev. A | Page 7 of 24

ADT7310 Data Sheet

0

0.05

0.10

0.15

0.20

0.25

0.30

2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

I

DD

(mA)

SUPPLY VOLTAGE (V)

I

DD

CONTINUO US CONVERSION

I

DD

1SPS

07789-008

07789-009

0

1

2

3

4

5

6

7

8

2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

SHUTDOWN I

DD

(µA)

SUPPLY VOLTAGE (V)

0

20

40

60

80

100

120

140

160

0

403530252015105

TEMPERATURE (°C)

TIME (Seconds)

07789-011

Figure 10. Average Operating Supply Current vs. Supply Voltage at 25°C

Figure 11. Shutdown Current vs. Supply Voltage at 25°C

Figure 12. Response to Thermal Shock

Rev. A | Page 8 of 24

Data Sheet ADT7310

THEORY OF OPERATION

CIRCUIT INFORMATION

The ADT7310 is a 13-bit digital temperature sensor that is
extendable to 16-bits for greater resolution. An on-board
temperature sensor generates a voltage proportional to absolute
temperature, which is compared to an internal voltage reference
and input to a precision digital modulator.

The on-board temperature sensor has excellent accuracy and
linearity over the entire rated temperature range without
needing correction or calibration by the user.

The sensor output is digitized by a sigma-delta (Σ-Δ)
modulator, also known as the charge balance type analog-to­digital converter. This type of converter utilizes time-domain
oversampling and a high accuracy comparator to deliver
16-bits of resolution in an extremely compact circuit.

Configuration register functions consist of

 Switching between 13-bit and 16-bit resolution
 Switching between normal operation and full power-down
 Switching between comparator and interrupt event modes

on the INT and CT pins

 Setting the active polarity of the CT and INT pins
 Setting the number of faults that activate CT and INT
 Enabling the standard one-shot mode and 1 SPS mode

CONVERTER DETAILS

The Σ-Δ modulator consists of an input sampler, a summing
network, an integrator, a comparator, and a 1-bit 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.

VOLTAGE REF

AND VPTAT

CLOCK

GENERATOR

TEMPERATURE MEASUREMENT

In normal mode, the ADT7310 runs an automatic conversion
sequence. During this automatic conversion sequence, a conver­sion takes 240 ms to complete and the ADT7310 is continuously
converting. This means that as soon as one temperature conver­sion is completed, another temperature conversion begins. Each
temperature conversion result is stored in the temperature value
register 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
asserts low. If the temperature exceeds 64°C, the INT pin asserts
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
register), a high temperature limit (stored in the 16-bit T
setpoint read/write register), and a low temperature limit (stored
in the 16-bit T
value exceeds these limits, the INT pin is activated; and if it
exceeds the T
pins are programmable for polarity via the configuration register,
and the INT and CT pins are also programmable for interrupt
mode via the configuration register.

setpoint read/write register). If the measured

LOW

limit, the CT pin is activated. The INT and CT

CRIT

Σ-∆ MODULATOR

INTEGRATOR

Figure 13. Σ-∆ Modulator

COMPARATOR

1-BIT

DAC

LPF DIGITAL

FILTER

CRIT

1-BIT

TEMPERATURE

VALUE

13-BIT

REGISTER

setpoint read/write

HIGH

7789-012

Rev. A | Page 9 of 24

ADT7310 Data Sheet

DIN

0x08 0x20

DATA

SCLK

DOUT

CS

WAIT 240ms MINIMUM

FOR CONVERSION TO FINISH

07789-026

Figure 14. Typical SPI One-Shot Write to Configuration Register Followed by a Read from the Temperature Value Register

ONE-SHOT MODE

When one-shot mode is enabled, the ADT7310 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, wait at least 240 ms
before reading back the temperature from the temperature value
register. This delay ensures that the ADT7310 has adequate time
to power up and complete a conversion.

To obtain an updated temperature conversion, reset Bits[6:5] of the
configuration register (Register Address 0x01) to 01.

1 SPS MODE

In this mode, the part performs one measurement per second.
A conversion takes only 60 ms, and it remains in the idle state
for the remaining 940 ms period. This mode is enabled by
writing 1 to Bit 6 and 0 to Bit 5 of the configuration register
(Register Address 0x01).

Rev. A | Page 10 of 24

Data Sheet ADT7310

TEMPERATURE
149°C

148°C
147°C
146°C
145°C
144°C
143°C
142°C
141°C
140°C

CT PIN

POLARITY = ACTIVE LOW

CT PIN

POLARITY =

ACTIVE HIGH

T

CRIT

T

CRIT

– T

HYST

TIME

*THERE IS A 240ms DELAY BETWEEN WRITI NG TO THE CONFIGURATION REGISTERT

O START
A STANDARD ONE-SHOT CONVERSION AND THE CT PIN GOING ACTIVE. THIS IS DUETO THE
CONVERSION TIME. THE DELAY IS 60ms IN THE CASE OF A ONE-SHOT CONVERSION.

WRITE TO

BIT 5 AND BIT 6 OF

CONFIGURATION

REGISTER.*

WRITE TO

BIT 5 AND BIT 6 OF

CONFIGURATION

REGISTER.*

WRITE TO

BIT 5 AND BIT 6 OF

CONFIGURATION

REGISTER.*

07789-013

CT and INT Operation in One-Shot Mode

See Figure 15 for more information on one-shot CT pin
operation for T

overtemperature events when one of the

CRIT

limits is exceeded. Note that in interrupt mode, a read from
any register resets the INT and CT pins.

For the INT pin in the comparator mode, if the temperature
drops below the T
T

value, a write to the one-shot bits (Bit 5 and Bit 6 of the

HYST

HIGH

– T

value or goes above the T

HYST

LOW

+

configuration register, Register Address 0x01) resets the INT pin.

For the CT pin in the comparator mode, if the temperature
drops below the T

CRIT

– T

value, a write to the one-shot

HYST

bits (Bit 5 and Bit 6 of the configuration register, Register
Address 0x01) resets the CT pin; see Figure 15.

Note that when using one-shot mode, ensure that the refresh
rate is appropriate to the application being used.

Figure 15. One-Shot CT Pin

Rev. A | Page 11 of 24

ADT7310 Data Sheet

07789-027

DIN

0x54

SCLK

DOUT

CS

TEMPERATURE

VALUE

TEMPERATURE

VALUE

TEMPERATURE

VALUE

CONTINUOUS READ MODE

When the command byte = 01010100 (0x54), the contents of
the temperature value register can be read out without requiring
repeated writes to the communications register. By sending 16
SCLK clocks to the ADT7310, the contents of the temperature
value register are output onto the DOUT pin.

To exit the continuous read mode, the Command Byte
01010000 (0x50) must be written to the ADT7310.

While in continuous read mode, the part monitors activity on
the DIN line so that it can receive the instruction to exit the
continuous read mode. Additionally, a reset occurs if 32
consecutive 1s are seen on the DIN pin. Therefore, hold DIN
low in continuous read mode until an instruction is to be
written to the device.

In continuous read mode, the temperature value register cannot
be read when a conversion is taking place. If an attempt is made
to read the temperature value register while a conversion is
taking place, then all 0s are read. This is because the continuous
read mode blocks read access to temperature value register
during a conversion.

SHUTDOWN

The ADT7310 can be placed in shutdown mode by writing 1
to Bit 6 and 1 to Bit 5 of the configuration register (Register
Address 0x01). The ADT7310 can be taken out of shutdown
mode by writing 0 to Bit 6 and 0 to Bit 5 of the configuration
register (Register Address 0x01). The ADT7310 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 ADT7310 even
when it is in shutdown mode. When the part is taken out of
shutdown mode, the internal clock is started and a conversion
is initiated.

FAULT QUEUE

Bit 0 and Bit 1 of the configuration register (Register Address
0x01) are used to set up a fault queue. Up to four faults are
provided to prevent false tripping of the INT and CT pins
when the ADT7310 is used in a noisy temperature environ­ment. The number of faults set in the queue must occur
consecutively to set the INT and CT outputs. For example,
if the number of faults set in the queue is four, then four
consecutive temperature conversions must occur, with each
result exceeding a temperature limit in any of the limit registers,
before the INT and CT pins are activated. If two consecutive
temperature conversions exceed a temperature limit and the
third conversion does not, the fault count is reset to zero.

Figure 16. Continuous Read Mode

Rev. A | Page 12 of 24

Data Sheet ADT7310

TEMPERATURE DATA FORMAT

One LSB of the ADC corresponds to 0.0625°C in 13-bit mode.
The ADC can theoretically measure a temperature range of
255°C, but the ADT7310 is guaranteed to measure a low value
temperature limit of −55°C to a high value temperature limit
of +150°C. The temperature measurement result is stored in
the 16-bit temperature value register and is compared with the
high temperature limits stored in the T
the T
temperature limit stored in the T

setpoint register. It is also compared with the low

HIGH

LOW

setpoint register and

CRIT

setpoint register.

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.

LOW

CRIT

Temperature data in the temperature value register, the T
setpoint register, the T

setpoint register, and the T

HIGH

setpoint register are represented by a 13-bit twos complement
word. The MSB is the temperature sign bit. The three LSBs,
Bit 0 to Bit 2, on power-up, are not part of the temperature
conversion result and are flag bits for T

CRIT

, T

HIGH

, and T

LOW

.
Tabl e 5 shows the 13-bit temperature data format without
Bit 0 to Bit 2.

The number of bits in the temperature data-word can be
extended to 16 bits, twos complement, by setting Bit 7 to 1
in the configuration register (Register Address 0x01). When
using a 16-bit temperature data value, Bit 0 to Bit 2 are not
used as flag bits and are instead the LSB bits of the temperature
value. The power-on default setting has a 13-bit temperature
data value.

Reading back the temperature from the temperature value register
requires a 2-byte read. Designers that use a 9-bit temperature
data format can still use the ADT7310 by ignoring the last four
LSBs of the 13-bit temperature value. These four LSBs are Bit 3
to Bit 6 in Tab l e 5.

Table 5. 13-Bit Temperature Data Format

Digital Output

Temperature

−55°C 1 1100 1001 0000 0x1C90

−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 0x000
+0.0625°C 0 0000 0000 0001 0x001
+25°C 0 0001 1001 0000 0x190
+50°C 0 0011 0010 0000 0x320
+125°C 0 0111 1101 0000 0x7D0
+150°C 0 1001 0110 0000 0x960

(Binary) Bits[15:3]

Digital
Output (Hex)

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. A | Page 13 of 24

ADT7310 Data Sheet

0x01

Configuration

0x00

when the status register is read and/or when the temperature measured goes back above the limit

when the status register is read and/or when the temperature measured goes back below the limit

when the status register is read and/or when the temperature measured goes back below the limit

REGISTERS

The ADT7310 contains eight registers:

• A status register

• A configuration register

• Five temperature registers

• An ID register

The status register, temperature value register, and the ID
register are read-on l y.

Table 6. ADT7310 Registers

Register
Address Description

Power-On
Default

0x00 Status 0x80

0x02 Temperature value 0x0000
0x03 ID 0xCX
0x04 T
0x05 T
0x06 T
0x07 T

setpoint 0x4980 (147°C)

CRIT

setpoint 0x05 (5°C)

HYST

setpoint 0x2000 (64°C)

HIGH

setpoint 0x0500 (10°C)

LOW

STATUS REGISTER

This 8-bit read-only register (Register Address 0x00) reflects the
status of the overtemperature and undertemperature interrupts
that can cause the CT and INT pins to go active. It also reflects the
status of a temperature conversion operation. The interrupt flags
in this register are reset by a read operation to the status register
and/or when the temperature value returns within the tempera­ture limits including hysteresis. The
from the temperature value register. In one-shot and 1 SPS
modes, the

RDY

bit is reset after a write to the one-shot bits.

RDY

bit is reset after a read

Table 7. Status Register (Register Address 0x00)

Default

Bit

Value Type Name Description

[3:0] 0000 R Unused Reads back 0.
4 0 R T

5 0 R T

6 0 R T

7 1 R

This bit is set to 1 when the temperature goes below the T

LOW

set in the T

This bit is set to 1 when the temperature goes above the T

HIGH

set in the T

This bit is set to 1 when the temperature goes above the T

CRIT

set in the T

This bit goes low when the temperature conversion result is written into the temperature value

RDY

LOW

HIGH

CRIT

register. It 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 one-shot bits.

+ T

setpoint registers.

HYST

− T

setpoint registers.

HYST

− T

setpoint registers.

HYST

temperature limit. The bit clears to 0

LOW

temperature limit. The bit clears to 0

HIGH

temperature limit. This bit clears to 0

CRIT

Rev. A | Page 14 of 24

Data Sheet ADT7310

01 = one shot. Conversion time is typically 240 ms.

CONFIGURATION REGISTER

This 8-bit read/write register stores various configuration modes
for the ADT7310, including shutdown, overtemperature and

Table 8. Configuration Register (Register Address 0x01)

Default

Bit

[1:0] 00 R/W Fault queue These two bits set the number of undertemperature/overtemperature faults that can

00 = 1 fault (default).
01 = 2 faults.
10 = 3 faults.
11 = 4 faults.
2 0 R/W CT pin polarity This bit selects the output polarity of the CT pin.
0 = active low.
1 = active high.
3 0 R/W INT pin polarity This bit selects the output polarity of the INT pin.
0 = active low.
1 = active high.
4 0 R/W INT/CT mode This bit selects between comparator mode and interrupt mode.
0 = interrupt mode.
1 = comparator mode.
[6:5] 00 R/W Operation mode These two bits set the operational mode for the ADT7310.
00 = continuous conversion (default). When one conversion is finished, the ADT7310

Value Type Name Description

occur before setting the INT and CT pins. This helps to avoid false triggering due to
temperature noise.

starts another.

undertemperature interrupts, one-shot, continuous conversion,
interrupt pins polarity, and overtemperature fault queues.

10 = 1 SPS mode. Conversion time is typically 60 ms. This operational mode reduces the

average current consumption.
11 = shutdown. All circuitry except interface circuitry is powered down.
7 0 R/W Resolution This bit sets up the resolution of the ADC when converting.
0 = 13-bit resolution. Sign bit + 12 bits gives a temperature resolution of 0.0625°C.
1 = 16-bit resolution. Sign bit + 15 bits gives a temperature resolution of 0.0078125°C.

Rev. A | Page 15 of 24

ADT7310 Data Sheet

2 0 R

T

flag/LSB2

Flags a T

event if the configuration register, Register Address 0x01[7] = 0

TEMPERATURE VALUE REGISTER

The temperature value register stores the temperature measured
by the internal temperature sensor. The temperature is stored as
a 16-bit twos complement format. The temperature is read back
from the temperature value register (Register Address 0x02) as a
16-bit value.

Bit 2, Bit 1, and Bit 0 are event alarm flags for T
T

. When the ADC is configured to convert the temperature

LOW

to a 16-bit digital value, Bit 2, Bit 1, and Bit 0 are no longer used
as flag bits and are, instead, used as the LSB bits for the extended
digital value.

CRIT

, T

HIGH

, and

ID REGISTER

This 8-bit read-only register stores the manufacturer ID in Bit 7
to Bit 3 and the silicon revision in Bit 2 to Bit 0.

T

SETPOINT REGISTER

CRIT

The 16-bit T
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 with the MSB being the temperature
sign bit.

setpoint register (Register Address 0x04)

CRIT

The default setting for the T

setpoint is 147°C.

CRIT

Table 9. Temperature Value Register (Register Address 0x02)

Bit Default Value Type Name Description

0 0 R T

flag/LSB0 Flags a T

LOW

(13-bit resolution). When the temperature value is below T

event if the configuration register, Register Address 0x01[7] = 0

LOW

, this bit it set to 1.

LOW,

Contains the Least Significant Bit 0 of the 15-bit temperature value if the

configuration register, Register Address 0x01[7] = 1 (16-bit resolution).

1 0 R T

flag/LSB1 Flags a T

HIGH

event if the configuration register, Register Address 0x01[7] = 0

HIGH

(13-bit resolution). When the temperature value is above T

, this bit it set to 1.

HIGH

Contains the Least Significant Bit 1 of the 15-bit temperature value if the

configuration register, Register Address 0x01[7] = 1 (16-bit resolution).

CRIT

(13-bit resolution). When the temperature value exceeds T

CRIT

, this bit it set to 1.

CRIT

Contains the Least Significant Bit 2 of the 15-bit temperature value if the

configuration register, Register Address 0x01[7] = 1 (16-bit resolution).
[7:3] 00000 R Temp Temperature value in twos complement format.
[14:8] 0000000 R Temp Temperature value in twos complement format.
15 0 R Sign Sign bit, indicates if the temperature value is negative or positive.

Table 10. ID Register (Register Address 0x03)

Bit Default Value Type Name Description

[2:0] XXX R Revision ID Contains the silicon revision identification number.
[7:3] 11000 R Manufacture ID Contains the manufacturer identification number.

Table 11. T

Setpoint Register (Register Address 0x04)

CRIT

Bit Default Value Type Name Description

[15:0] 0x4980

R/

W

16-bit critical overtemperature limit, stored in twos complement format.

T

CRIT

Rev. A | Page 16 of 24

Data Sheet ADT7310

T

SETPOINT REGISTER

HYST

The T
the temperature hysteresis value for the T

setpoint 8-bit register (Register Address 0x05) stores

HYST

, T

LOW

, and T

HIGH

CRIT

temperature limits. The temperature hysteresis value is stored in
straight binary format using four LSBs. Increments are possible
in steps of 1°C from 0°C to 15°C. The value in this register is
subtracted from the T
T

value to implement hysteresis.

LOW

The default setting for the T

T

SETPOINT REGISTER

HIGH

The 16-bit T

setpoint register (Register Address 0x06) stores

HIGH

HIGH

and T

CRIT

setpoint is 5°C.

HYST

values and added to the

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 with the most significant
bit being the temperature sign bit.

The default setting for the T

T

SETPOINT REGISTER

LOW

The 16-bit T

setpoint register (Register Address 0x07) stores

LOW

setpoint is 64°C.

HIGH

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 with the MSB
being the temperature sign bit.

The default setting for the T

setpoint is 10°C.

LOW

Table 12. T

Setpoint Register (Register Address 0x05)

HYST

Bit Default Value Type Name Description

[3:0] 0101

[7:4] 0000

Table 13. T

HIGH

R/

W

R/

W

Setpoint Register (Register Address 0x06)

Hysteresis value, from 0°C to 15°C. Stored in straight binary format. The default setting is 5°C.

T

HYST

N/A Not used.

Bit Default Value Type Name Description

[15:0] 0x2000

Table 14. T

Setpoint Register (Register Address 0x07)

LOW

R/

W

16-bit overtemperature limit, stored in twos complement format.

T

HIGH

Bit Default Value Type Name Description

[15:0] 0x0500

R/

W

16-bit undertemperature limit, stored in twos complement format.

T

LOW

Rev. A | Page 17 of 24

ADT7310 Data Sheet

ADT7310

GND

SCLK
DOUT
DIN

CT

INT

V

DD

10kΩ10kΩ

PULL-UP

V

DD

0.1µF

MICROCONTROLLER

V

DD

07789-014

CS

SERIAL INTERFACE

Figure 17. Typical SPI Interface Connection

The ADT7310 has a 4-wire serial peripheral interface (SPI). The
interface has a data input pin (DIN) for inputting 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

the serial interface.

is required for correct operation of the

CS

) enables or disables

interface. Data is clocked out of the ADT7310 on the negative
edge of SCLK, and data is clocked into the device on the
positive 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. This
indicates to the ADT7310 whether the transaction is a read or
a write and provides the address of the register for the data
transfer. Tab l e 15 shows the command byte.

Table 15. Command Byte

C7 C6 C5 C4 C3 C2 C1 C0

0 R/W Register address Continuous

read

0 0

Bit C7 of the command byte must be set to 0 to successfully
begin a bus transaction. The SPI interface does not work
correctly if a 1 is written into this bit.

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.

Bit C2 activates a continuous read mode on the temperature
value register only. When this bit is set, the serial interface is
configured so that the temperature value register can be
continuously read. When the command word is 01010100
(0x54), the contents of the temperature value register can be
read out without requiring repeated writes to set the address
bits. Simply sending 16 SCLK clocks to the ADT7310 clocks the
contents of the temperature value register onto the DOUT pin.

Rev. A | Page 18 of 24

Data Sheet ADT7310

K

WRITING DATA

Data is written to the ADT7310 in eight 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 ADT7310 clocks the data into the register addressed in
the command byte on the positive edge of SCLK. The master
finishes the write by pulling

CS

CS

high.

Figure 18 shows a write to an 8-bit register, and Figure 19 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.

SCL

DIN

1234

8-BIT COMMAND BYTE

0

R/W REGI STER ADDR

C5

C6

C7

5 6 7 8 9 10111213141516

8-BIT DATA

CONT

00

READ

C4

C3

C2

C0

C1

D5

D4 D3D7 D6

D2 D1 D0

07789-028

Figure 18. Writing to an 8-Bit Register

CS

SCLK

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

CONT

0

READ

C3 C2C5 C4

0

C0

D14 D13

D12 D10D11 D9 D8 D7D15

17

22 23

07789-029

Figure 19. Writing to a 16-Bit Register

CS

SCLK

DIN

DOUT

1234

8-BIT COMMAND WORD

0

R/W REGISTER ADDR

C6

C7

C5

5 6 7 8 9 10111213141516

CONT

0

READ

C4

C3

C2

0

C0

C1

8-BIT DATA

D6 D5

D4 D3 D2 D1 D0D7

07789-030

Figure 20. Read from an 8-Bit Register

Rev. A | Page 19 of 24

ADT7310 Data Sheet

C3

C2

C5

C4

DIN

C7

C6

C1

D2

D1

D0

C0

16-BIT DATA

5246 7 8 9 10 11 12 13 14 15 16

22 23

SCLK

1 2 3 4

D14

D13

17

CS

R/W

REGIST E R ADDR

0

0

0

CONT
READ

D12

D11

D10

D9

D8

D7

D15

DOUT

07789-031

8-BIT COMMAND BYTE

Figure 21. Read from a 16-Bit Register

READING DATA

A read transaction begins when the master writes the command
byte to the ADT7310 with the read/write bit set to 1. The master
then supplies 8 or 16 clock pulses, depending on the addressed
register, and the ADT7310 clocks out data from the addressed
register on the DOUT line. Data is clocked out on the first
falling edge of SCLK following the command byte.

The read transaction finishes when the master takes

CS

high.

The master must begin a new read transaction on the bus for
every register read. Only one register is read per bus transaction.
However, in continuous read mode, Command Byte C2 = 1, and
the temperature value register can be read from continuously.
The master sends 16 clock pulses on SCLK, and the temperature
value is clocked out on DOUT.

INTERFACING TO DSPs OR MICROCONTROLLERS

The ADT7310 can be operated with CS used as a frame syn­chronization signal. This scheme is useful for DSP interfaces.

CS

In this case, the first bit (MSB) is effectively clocked out by

CS

because

normally occurs after the falling edge of SCLK in

DSPs. SCLK can continue to run between data transfers,
provided that the timing numbers are obeyed.

CS

can be tied to ground, and the serial interface can be
operated in a 3-wire mode. DIN, DOUT, and SCLK are
used to communicate with the ADT7310 in this mode.

For microcontroller interfaces, it is recommended that SCLK
idle high between data transfers.

SERIAL INTERFACE RESET

The serial interface can be reset by writing a series of 1s on the
DIN input. If a Logic 1 is written to the ADT7310 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
interface gets lost due to a software error or some glitch in the
system. Reset returns the interface to the state in which it is
expecting a write to the communications register. This opera­tion resets the contents of all registers to their power-on values.
Following a reset, the user should allow a period of 500 µs
before addressing the serial interface.

Rev. A | Page 20 of 24

Data Sheet ADT7310

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

07789-020

INT AND CT OUTPUTS

The INT and CT pins are open drain outputs, and both pins
require a 10 kΩ pull-up resistor to V

DD

.

UNDERTEMPERATURE AND OVERTEMPERATURE DETECTION

The INT and CT pins have two undertemperature/over­temperature modes: comparator mode and interrupt mode.
The interrupt mode is the default power-up overtemperature
mode. The INT output pin becomes active when the tempera­ture is greater than the temperature stored in the T
register or less than the temperature stored in the T
register. How this pin reacts after this event depends on the
overtemperature mode selected.

Figure 22 illustrates the comparator and interrupt modes for
events exceeding the T

limit with both pin polarity settings.

HIGH

Figure 23 illustrates the comparator and interrupt modes for
events exceeding the T

limit with both pin polarity settings.

LOW

HIGH

LOW

setpoint
setpoint

Comparator Mode

In comparator mode, the INT pin returns to its inactive status
when the temperature drops below the T
rises above the T

LOW

+ T

HYST

limit.

HIGH

− T

HYST

limit or

Putting the ADT7310 into shutdown mode does not reset the
INT state in comparator mode.

Interrupt Mode

In interrupt mode, the INT pin goes inactive when any ADT7310
register is read. Once the INT pin is reset, it goes active again
only when the temperature is greater than the temperature
stored in the T
stored in the T

setpoint register or less than the temperature

HIGH

setpoint register.

LOW

Placing the ADT7310 into shutdown mode resets the INT pin
in the interrupt mode.

Figure 22. INT Output Temperature Response Diagram for T

Rev. A | Page 21 of 24

Overtemperature Events

HIGH

ADT7310 Data Sheet

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

07789-021

Figure 23. INT Output Temperature Response Diagram for T

Undertemperature Events

LOW

Rev. A | Page 22 of 24

Data Sheet ADT7310

0.1µF

ADT7310

TTL/CMOS

LOGIC

CIRCUITS

POWER
SUPPLY

07789-022

APPLICATIONS INFORMATION

THERMAL RESPONSE TIME

The time required for a temperature sensor to settle to a
specified accuracy is a function of the thermal mass of the
sensor and the thermal conductivity between the sensor and
the object being sensed. Thermal mass is often considered
equivalent to capacitance. Thermal conductivity is commonly
specified using the symbol, Q, and can be thought of as thermal
resistance. It is commonly specified in units of degrees per watt
of power transferred across the thermal joint. The time required
for the part to settle to the desired accuracy is dependent on the
thermal contact established in that particular application, and
the equivalent power of the heat source. In most applications,
the settling time is best determined empirically.

SUPPLY DECOUPLING

The ADT7310 should be decoupled with a 0.1 µF ceramic
capacitor between V
when the ADT7310 is mounted remotely from the power supply.
Precision analog products, such as the ADT7310, require a well­filtered power source.

Because the ADT7310 operates from a single supply, it may
seem convenient to tap into the digital logic power supply.
Unfortunately, the logic supply is often a switch-mode design,
which generates noise in the 20 kHz to 1 MHz range. In addi­tion, fast logic gates can generate glitches hundreds of millivolts
in amplitude due to wiring resistance and inductance.

and GND. This is particularly important

DD

TEMPERATURE MONITORING

The ADT7310 is ideal for monitoring the thermal environment
within hazardous automotive applications. The die accurately
reflects the exact thermal conditions that affect nearby
integrated circuits.

The ADT7310 measures and converts the temperature at the
surface of its own semiconductor chip. When the ADT7310 is
used to measure the temperature of a nearby heat source, the
thermal impedance between the heat source and the ADT7310
must be considered.

When the thermal impedance is determined, the temperature
of the heat source can be inferred from the ADT7310 output.
As much as 60% of the heat transferred from the heat source to
the thermal sensor on the ADT7310 die is discharged via the
copper tracks and the bond pads. Of the pads on the ADT7310,
the GND pad transfers most of the heat. Therefore, to measure
the temperature of a heat source, it is recommended that the
thermal resistance between the ADT7310 GND pad and the
GND of the heat source be reduced as much as possible.

If possible, the ADT7310 should be powered directly from the
system power supply. This arrangement, shown in Figure 24,
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. This decoupling capacitor must be placed as close
as possible to the V

Figure 24. Use of Separate Traces to Reduce Power Supply Noise

pin of the ADT7310.

DD

Rev. A | Page 23 of 24

ADT7310 Data Sheet

CONTROLLING DIMENSIONSARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLYAND ARE NOTAPPROPRIATE FORUSE IN DESIGN.

COMPLIANT TO JEDEC STANDARDS MS-012-AA

012407-A

0.25 (0.0098)

0.17 (0.0067)

1.27 (0.0500)

0.40 (0.0157)

0.50 (0.0196)

0.25 (0.0099)

45°

8°
0°

1.75 (0.0688)

1.35 (0.0532)

SEATING

PLANE

0.25 (0.0098)

0.10 (0.0040)

4

1

8 5

5.00(0.1968)

4.80(0.1890)

4.00 (0.1574)

3.80 (0.1497)

1.27 (0.0500)
BSC

6.20 (0.2441)

5.80 (0.2284)

0.51 (0.0201)

0.31 (0.0122)

COPLANARITY

0.10

©2009–2011 Analog Devices, Inc. All rights reserved. Trademarks and

OUTLINE DIMENSIONS

Figure 25. 8-Lead Standard Small Outline Package [SOIC_N]

Narrow Body

(R-8)

Dimensions shown in millimeters and (inches)

ORDERING GUIDE

Model1 Temperature Range Temperature Accuracy2 Package Description Package Option

ADT7310TRZ –55°C to +150°C ±0.5°C 8-Lead SOIC_N R-8
ADT7310TRZ-REEL –55°C to +150°C ±0.5°C 8-Lead SOIC_N R-8
ADT7310TRZ-REEL7 –55°C to +150°C ±0.5°C 8-Lead SOIC_N R-8
EVAL-ADT7X10EBZ Evaluation Board

1

Z = RoHS Compliant Part.

2

Maximum accuracy over the −40°C to +105°C temperature range.

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D07789-0-12/11(A)

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