ANALOG DEVICES ADT7410 Service Manual

±0.5°C Accurate, 16-Bit Digital

www.BDTIC.com/ADI

I2C Temperature Sensor

Preliminary Technical Data

FEATURES

16-bit temperature-to-digital converter
Temperature accuracy ±0.5°C from 0°C to 70°C
Power saving 1 Sample Per Second mode

2

I

C-compatible interface
Operating temperature range : −55°C to +150°C
Operating voltage range: 2.7 V to 5.5 V
Critical overtemperature indicator
Programmable overtemperature/undertemperature interrupt
Shutdown mode for low power consumption
Power consumption 1 mW typical at 3.3 V
Standard 8-lead narrow SOIC RoHS-compliant package

APPLICATIONS

Medical equipment
Isolated sensors
Environmental control systems
Computer thermal monitoring
Thermal protection
Industrial process control
Power system monitors
Hand-held applications

3

A0

4

A1

TEMPERATURE

VALUE

REGISTE R

CONFIGURAT ION

REGISTE R

T

CRIT

REGISTE R

T

HIGH

REGISTE R

T

LOW

REGISTE R

T

HYST

REGISTE R

V

DD

8

INTERNAL

REFERENCE

TEMPERATURE

SENSOR

POINTER

REGISTER

SMBus/I2C INTERFACE

7

GND

Figure 1.

INTERNAL

OSCILLATOR

Σ-Δ

MODULATO R

FILTER

LOGIC

ADT7410

T

CRIT

T

HIGH

T

LOW

ADT7410

6

CT

5

INT

1

SCL

2

SDA

06560-001

FUNCTIONAL BLOCK DIAGRAM

GENERAL DESCRIPTION

The ADT7410 is a high accuracy digital temperature sensor
in a narrow SOIC package. It contains a band gap temperature
sensor and a13-bit ADC, to monitor and digitize the
temperature to a resolution of 0.0625°C. The resolution
can be changed to 16 bits by setting a bit in the configuration
register, to give a 0.0078°C resolution. The default resolution
is 13 bits.

The ADT7410 is guaranteed to operate at supply voltages from

2.7 V to 5.5 V. Operating at 3.3 V, the average supply current is
typically 250 A. The ADT7410 offers a shutdown mode that
powers down the device and gives a shutdown current of typically

0.8 A. The ADT7410 is rated for operation over the −55°C to
+150°C temperature range.

Pins A0 and A1 are available for address selection, giving the
ADT7410 4 possible I

2

C addresses. 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.

Rev. PrE

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rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] ©2008 Analog Devices, Inc. All rights reserved.

ADT7410 Preliminary Technical Data

www.BDTIC.com/ADI

PRODUCT HIGHLIGHTS

• An on-chip temperature sensor allows an accurate

measurement of the ambient temperature. The
measurable temperature range is −55°C to +150°C.

• Supply voltage is 2.7 V to 5.5 V.

• Available in an 8-lead narrow SOIC package.

• Temperature accuracy is ±0.5°C maximum.

• Default temperature resolution is 0.0625°C.

• First conversion on power-up is a fast conversion to

ensure fast CT and INT pin activation in
overtemperature situations.

• Programmable temperature interrupt limits.

• Shutdown mode reduces the current consumption to

0.8 A typical.

• Connect up to four ADT7410 devices to a single I

bus.

2

C®

Rev. PrE | Page 2 of 27

Preliminary Technical Data ADT7410

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TABLE OF CONTENTS

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

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

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

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

Product Highlights ............................................................................ 2

Revision History ................................................................................ 3

Specifications ..................................................................................... 4

2

I

C Timing Specifications ............................................................ 5

Timing Diagram ............................................................................ 5

Absolute Maximum Ratings ............................................................ 6

ESD Caution .................................................................................. 6

Pin Configuration and Function Descriptions ............................. 7

Typical Performance Characteristics .............................................. 8

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

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

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

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

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

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

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

Temperature Data Format .......................................................... 12

Registers ............................................................................................ 13

Address Pointer Register ............................................................ 13

Temperature Value Registers ..................................................... 13

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

Configuration Register ............................................................... 14

T

Setpoint Registers ............................................................. 15

HIGH

T

Setpoint Registers .............................................................. 15

LOW

T

Setpoint Registers .............................................................. 15

CRIT

T

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

HYST

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

Serial Interface ................................................................................. 17

Writing Data ................................................................................ 18

Reading Data ............................................................................... 19

INT Output Overtemperature Modes .......................................... 21

Comparator Mode ...................................................................... 21

Interrupt Mode ............................................................................ 21

Application Information ................................................................ 23

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

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

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

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

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

REVISION HISTORY

08/08 - Revision PrE: Preliminary Version E

04/08 - Revision PrD: Preliminary Version D

12/07 – Revision PrC: Preliminary Version C

11/07—Revision PrB: Preliminary Version B

08/07—Revision PrA: Preliminary Version A

Rev. PrE | Page 3 of 27

ADT7410 Preliminary Technical Data

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SPECIFICATIONS

TA = −55°C to +150°C, V

Table 1.

Parameter Min Typ Max Unit Test Conditions/Comments

TEMPERATURE SENSOR AND ADC

Accuracy ±0.5 °C TA = 0°C to +70°C
±0.5 °C TA = -20°C to +100°C, VDD = 3.3 V
±1.5 °C TA = −40°C to +125°C
±2 °C TA = −55°C to +150°C
ADC Resolution 13 Bits

16 Bits

Temperature Resolution

13 Bits 0.0625 °C

16 Bits 0.0078125 °C

Temperature Conversion Time 240 ms

Fast Temperature Conversion

Time

1 SPS Conversion Time 60 ms Conversion time for one sample per second mode

Fast Temperature Conversion

Accuracy
±TBD ±TBD °C TA = −40°C to +125°C
±TBD ±TBD °C TA = −55°C to +150°C
Long-Term Drift 0.08 °C Drift over 10 years, if part is operated at 55°C
Temperature Hysteresis 0.02 °C Temperature cycl = 25°C to 125°C, and back to 25°C
Repeatability 0.01 ? °C TA = +25°C

DC PSRR TBD °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, I
Output Low Voltage, VOL 0.4 V IOL = 3 mA
Output High Voltage, VOH 0.7 × VDD V
Output Capacitance, C
RON Resistance (Low Output) 15 Ω Supply and temperature dependent

DIGITAL INPUTS

Input Current ±1 μA VIN = 0 V to VDD
Input Low Voltage, VIL 0.3 × VDD V
Input High Voltage, VIH 0.7 × VDD V
SCL, SDA Glitch Rejection 50 ns

Pin Capacitance 3 10 pF

POWER REQUIREMENTS

Supply Voltage 2.7 5.5 V
Supply Current at 3.3 V TBD TBD μA Peak current while converting and I2C interface inactive
Supply Current at 5.0 V TBD 350 μA Peak current while converting and I2C interface inactive
Shutdown Mode at 3.3 V TBD TBD μA Supply current in shutdown mode
Shutdown Mode at 5.0 V TBD 1 μA Supply current in shutdown mode
Power Dissipation TBD μW VDD = 3.3 V, normal mode at 25°C

1 Sample Per Second 150 μW Power dissipated for VDD = 3.3 V at 25°C
1 Sample Per Second 315 μW Power dissipated for VDD = 5.0 V at 25°C

= 2.7 V to 5.5 V, unless otherwise noted.

DD

6 10 ms First conversion on power-up only

±TBD ±TBD °C T

OH

OUT

1 mA VOH = 5 V

3 10 pF

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

Twos complement temperature value of sign bit plus
15 ADC bits (D7 = 1 in the configuration register)

13-bits (Sign + 12-bit)

16-bit (Sign + 15-bit)

Continuous conversion mode and one-shot
conversion mode

= 0°C to +70°C

A

Input filtering suppresses noise spikes of less
than 50 ns

Rev. PrE | Page 4 of 27

Preliminary Technical Data ADT7410

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I2C 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 tR (rise time) = tF (fall time) = 5 ns
(10% to 90% of V

Table 2.

Parameter1 Symbol Min Typ Max Unit Comments

Serial Clock Period t1 2.5 μs Fast mode I2C. See Figure 2.
Data In Setup Time to SCL High t2 50 ns See Figure 2.
Data Out Stable After SCL Low t3 0 0.92 ns Fast mode I2C. See Figure 2.
Data Out Stable After SCL Low t3 0 3.452 μs Standard mode I2C. See Figure 2.
SDA Low Setup Time to SCL Low (Start Condition) t4 50 ns See Figure 2.
SDA High Hold Time After SCL High (Stop Condition) t5 50 ns See Figure 2.
SDA and SCL Rise Time t6 300 ns Fast mode I2C. See Figure 2.
SDA and SCL Rise Time t6 1000 ns Standard mode I2C. See Figure 2.
SDA and SCL Fall Time t7 300 ns See Figure 2.
Capacitive Load for each Bus Line

1

Guaranteed by design and characterization; not production tested.

2

This time has to be met only if the master does not stretch the low period of the SCL signal.

TIMING DIAGRAM

) and timed from a voltage level of 1.6 V.

DD

SCL

t

4

SDA

DATA IN

SDA

DATA OUT

CB 400 pF

t

1

t

2

t

3

Figure 2 I2C Timing Diagram

t

5

t

t

7

6

06560-002

Rev. PrE | Page 5 of 27

ADT7410 Preliminary Technical Data

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ABSOLUTE MAXIMUM RATINGS

Table 3.

Parameter Rating

VDD to GND –0.3 V to +7 V
SDO Input Voltage to GND –0.3 V to VDD + 0.3 V
SDO Output Voltage to GND –0.3 V to VDD + 0.3 V
SCL 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
Operating Temperature Range –55°C to +150°C
Storage Temperature Range –65°C to +160°C
Maximum Junction Temperature, T

150.7°C

JMAX

8-Lead N-SOIC (R-8)

Power Dissipation1 W

MAX

= (T

JMAX

− T

2

A

)/θJA

Thermal Impedance3

θJA, Junction-to-Ambient (Still Air) 157°C/W
θJC, Junction-to-Case 56°C/W

IR Reflow Soldering

Peak Temperature (RoHS-Compliant

260°C (+0°C)

Package)
Time at Peak Temperature 20 sec to 40 sec
Ramp-Up Rate 3°C/sec maximum
Ramp-Down Rate –6°C/sec maximum
Time from 25°C to Peak Temperature 8 minutes maximum

1

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

worst-case θJA and θJC. Refer to Figure 3 for a plot of maximum power
dissipation vs. ambient temperature (TA).

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.

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.

Figure 3. SOIC_N Maximum Power Dissipation vs. Temperature

ESD CAUTION

I

(1.6mA WITH VDD = 5V,

SINK

100µA WIT H V

TO

OUTPUT

PIN

50pF

I

SOURCE

100µA WIT H V

Figure 4. Load Circuit for Timing Characterization

Rev. PrE | Page 6 of 27

= 3V)

DD

1.6V

(200µA WIT H VDD = 5V,

= 3V)

DD

06791-002

Preliminary Technical Data ADT7410

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PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

1

SCL

SDA

AD7410

2

A0

3

TOP VIEW

(Not to Scale)

A1

4

Figure 5. Pin Configuration

8

V

DD

GND

7

CT

6

INT

5

06560-004

Table 4. Pin Function Descriptions

Pin No. Mnemonic Description

1 SCL

Serial Clock Input. This is the clock input for the serial port. The serial clock is used to clock in and clock out data to
and from any register of the ADT7410. Open-drain configuration; needs a pull-up resistor.

2 SDA

2

C Serial Data Input/Output. Serial data to and from the part is provided on this pin. Open-drain configuration;

I

needs a pull-up resistor.
3 A0 I2C Serial Bus Address Selection Pin. Logic input. Connect to GND or VDD to set I2C address.
4 A1 I2C Serial Bus Address Selection Pin. Logic input. Connect to GND or VDD to set I2C address.
5 INT

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

interrupt. Open-drain configuration; needs a pull-up resistor.
6 CT

Critical Overtemperature Indicator. Power-up default polarity is active low. Open-drain configuration; needs a pull-

up resistor.
7 GND Analog and Digital Ground.
8 VDD Positive Supply Voltage, 2.7 V to 5.5 V. The supply should be decoupled to ground.

Rev. PrE | Page 7 of 27

ADT7410 Preliminary Technical Data

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TYPICAL PERFORMANCE CHARACTERISTICS

Figure 6. Temperature Accuracy at 3.3 V and 5 V

Figure 7. Operating Supply Current vs. Temperature

Figure 9. Shutdown Current vs. Supply Voltage at 30°C

Figure 10. Temperature Accuracy vs. Supply Ripple Frequency

Figure 8. Average Operating Supply Current vs. Supply Voltage at 30°C

Rev. PrE | Page 8 of 27

Figure 11. Response to Thermal Shock

Preliminary Technical Data ADT7410

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THEORY OF OPERATION

CIRCUIT INFORMATION

The ADT7410 is a 16-bit digital temperature sensor with the 16th
bit acting as the sign bit. An on-board temperature sensor generates
a voltage precisely proportional to absolute temperature, which is
compared to an internal voltage reference and input to a precision
digital modulator. Overall accuracy for the ADT7410 is ±0.5°C
from 0°C to +70°C. The serial interface is I

2

C compatible and the
open-drain outputs of the ADT7410, INT and CT, are capable of
sinking 2 mA.

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 ∑-∆ modulator, also known
as the charge balance type analog-to-digital converter. This type
of converter utilizes time-domain oversampling and a high
accuracy comparator to deliver 16 bits of effective accuracy in
an extremely compact circuit.

The measured temperature value is compared with a critical
temperature limit stored in the 16-bit T
a high temperature limit stored in the 16-bit T
register and a low temperature limit stored in the 16-bit T

read/write register,

CRIT

read/write

HIGH

LOW

read/write register. If the measured value exceeds these limits,
the INT pin is activated, and if it exceeds the T

limit, the CT

CRIT

pin is activated. The INT and CT pins are programmable for
polarity via the configuration register while the INT and CT pins
are also programmable for mode operation via the configuration
register.

Configuration register functions consist of:

• Switching between normal operation and full power-down.

• Switching between comparator and interrupt event modes

on the INT and CT pins.

• Setting the CT and INT pins active polarity.

• Setting the number of faults that activate the CT and

INT pins.

• Enabling the standard one-shot mode and one sample per

second mode.

CONVERTER DETAILS

The Σ-∆ 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 I

2

C temperature data.

Δ-Σ MODULATOR

VOLTAGE REF

AND VPTAT

CLOCK

GENERATOR

INTEGRATOR

Figure 12. Σ-Δ Modulator

COMPARATOR

1-BIT

DAC

LPF DIGITAL

FILTER

1-BIT

13-BIT

TEMPERATURE

VAL UE

REGISTER

TEMPERATURE MEASUREMENT

In normal mode, the ADT7410 runs an automatic conversion
sequence. During this automatic conversion sequence, a
conversion takes 240 ms to complete and the ADT7410 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

2

I

C interface.

On power-up, the first conversion is a fast conversion, taking
typically 6 ms. Therefore, the CT and INT pins are activated
very quickly after power-up if an overtemperature event is
present at power-up.

The conversion clock for the part is generated internally.
No external clock is required except when reading from and
writing to the serial port.

In continuous conversion mode, the internal clock is reset after
every read or write operation. This causes the device to start a
temperature conversion after every read or write, the result of
which is typically available 240 ms later. Reading from the
device before a conversion is complete causes the ADT7410 to
finish converting and store the result in a shadow temperature
value register. The read operation provides the previous
conversion result. As soon as communication to the ADT7410
is complete, the result in the temporary temperature value
register is moved into the live temperature value register that
can be accessed by the I

The measured temperature value is compared with a critical
temperature limit, stored in the 16-bit T
a high temperature limit, stored in the 16-bit T
register, and a low temperature limit, stored in the 16-bit T
read/write register. If the measured value exceeds these limits, the
INT pin is activated and if it exceeds the T
activated. This INT and CT pins are programmable for polarity

2

C interface.

read/write register,

CRIT

read/write

HIGH

limit, the CT pin is

CRIT

LOW

06560-011

Rev. PrE | Page 9 of 27