Analog Devices ADT7302 pre Datasheet

±2°C Accurate, MicroPower Digital

GND

Temperature Sensor in 6-Lead SOT-23

Preliminary Technical Data

FEATURES

13-bit temperature-to-digital converter

−40°C to +125°C operating temperature range
±2°C accuracy

0.03125°C temperature resolution
Shutdown current of 1 µA
Power dissipation of 0.631 mW at V
SPI- and DSP-compatible serial interface
Shutdown mode
Space-saving SOT-23 and MSOP packages

APPLICATIONS

Medical equipment
Automotive:
Environmental controls
Oil temperature
Hydraulic systems
Cell phones
Hard disk drives
Personal computers
Electronic test equipment
Office equipment
Domestic appliances
Process control

GENERAL DESCRIPTION

The ADT7302 is a complete temperature monitoring system
available in SOT-23 and MSOP packages. It contains a band gap
temperature sensor and a 13-bit ADC to monitor and digitize
the temperature reading to a resolution of 0.03125°C.

= 3.3 V

DD

ADT7302

FUNCTIONAL BLOCK DIAGRAM

BAND GAP

TEMPERATURE

SENSOR

ADT7302

INTERFACE

Figure 1. Functional Bloc k Diagram

PRODUCT HIGHLIGHTS

1. The ADT7302 has an on-chip temperature sensor that

allows an accurate measurement of the ambient tempera­ture. The measurable temperature range is −40°C to
+125°C.

13-BIT

ANALOG/DIGITAL

CONVERTER

TEMPERATURE

VALUE

REGISTER

SERIAL

BUS

V

DD

CS
SCLK
DIN
DOUT

04662-C-001

The ADT7302 has a flexible serial interface that allows easy
interfacing to most microcontrollers. The interface is compat­ible with SPI®, QSPI™, and MICROWIRE™ protocols as well as
DSPs. The part features a standby mode that is controlled via
the serial interface.

The ADT7302’s wide supply voltage range, low supply current,
and SPI compatible interface make it ideal for a variety of
applications, including personal computers, office equipment,
automotive, and domestic appliances.

Rev. PrE

Information fu rnished by Analog Devices is believed to be accu rate and re liable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered tr ademarks are th e property of th eir respective o wners.

2. Supply voltage of 2.7 V to 5.5 V.

3. Space-saving 6-lead SOT-23 and 8-lead MSOP packages.

4. Temperature accuracy of ±2°C.

5. 13-bit temperature reading to 0.03125°C resolution.

6. The ADT7302 features a shutdown mode that reduces the

power consumption to 4.88 µW with VDD = 3.3 V @ 1 SPS.

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

www.analog.com

© 2004 Analog Devices, Inc. All rights re served.

ADT7302 Preliminary Technical Data

TABLE OF CONTENTS

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

Temperature Value Register ........................................................ 8

Timing Characteristics.................................................................4

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

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

Pin Configurations and Function Descriptions............................6

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

Circuit Information ..........................................................................8

Converter Details..........................................................................8

REVISION HISTORY

Revision PrE: Preliminary Version

Serial Interface .............................................................................. 9

Microprocessor Interfacing....................................................... 10

Mounting The ADT7302........................................................... 12

Supply Decoupling ..................................................................... 12

Outline Dimensions....................................................................... 13

Ordering Guide............................................................................... 14

Rev. PrE | Page 2 of 14

Preliminary Technical Data ADT7302

SPECIFICATIONS

TA = T

Table 1.

Parameter Min Typ Max Unit Test Conditions/Comments

TEMPERATURE SENSOR AND ADC VDD = +3.3 V (±10%) and 5 V (±10%)

TBD ±2.5 °C TA = −20°C to +85°C.
TBD ±3 °C TA = −40°C to +125°C.

SUPPLIES

190 300 µA VDD = 3.3 V. Powered up and not converting

1.6 2.2 mA VDD = 5 V. Powered up and converting
280 400 µA VDD = 5 V. Powered up and not converting

0.2 1 µA VDD = 5 V.

7.4 µW VDD = 5 V

65 µW VDD = 5 V

641 µW VDD = 5 V
DIGITAL INPUT3

DIGITAL OUTPUT

1

Thermal Time Constant is the time it takes for a starting temperature difference to change to 36.8% of it’s starting value. For example if the ADT7302 experienced a

thermal shock from 0°C to 100°C, it would take typically 2 secs for the ADT7302 to reach 63.2°C.

2

The ADT7302 is taken out of shutdown mode and a temperature conversion is immediately performed after this write operation. Once the temperature conversion is

complete, the ADT7302 is put back into shutdown mode.

3

Guaranteed by design and characterization, not production tested.

to T

MIN

, VDD = 2.7 V to 5.5 V, unless otherwise noted. All specifications apply for –40°C to +125°C, unless otherwise stated

MAX

Accuracy TBD ±2 °C TA = 0°C to 70°C.

Temperature Resolution 0.03125 °C
Auto Conversion Update Rate, tR 1 sec Temperature measurement every 1 second
Temperature Conversion Time 2 ms
Thermal Time Constant1 2 sec

Supply Voltage 2.7 5.5 V For Specified performance.
Supply Current

Normal Mode 1.6 2.2 mA VDD = 3.3 V. Powered up and converting

Shutdown Mode 0.2 1 µA VDD = 3.3 V.

Power Dissipation

Normal Mode (Average) 631 µW VDD = 3.3 V. Auto conversion update, tR.

1.41 mW VDD = 5 V. Auto conversion update, tR.
Shutdown Mode (Average)2

1 SPS 4.88 µW VDD = 3.3 V

10 SPS 42.9 µW VDD = 3.3 V

100 SPS 423 µW VDD = 3.3 V

Input High Voltage, VIH 2.5 V
Input Low Voltage, VIL 0.8 V
Input Current, IIN ±1 µA VIN = 0 V to VDD
Input Capacitance, CIN 10 pF All digital inputs

3

Output High Voltage, VOH V

− 0.3 V I

DD

SOURCE

= I

= 200 µA

SINK

Output Low Voltage, VOL 0.4 V IOL = 200 µA
Output Capacitance, C

50 pF

OUT

Rev. PrE | Page 3 of 14

ADT7302 Preliminary Technical Data

TIMING CHARACTERISTICS

Guaranteed by design and characterization, not production tested. 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. See Figure 3.

TA = T

MIN

to T

, VDD = 2.7 V to 5.5 V, unless otherwise noted.

MAX

Table 2.

Parameter Limit Unit Comments

t1 5 ns min

CS

to SCLK Setup Time
t2 25 ns min SCLK High Pulse Width
t3 25 ns min SCLK Low Pulse Width
t4 1 35 ns max Data Access Time after SCLK Falling Edge
t

5

20 ns min Data Setup Time prior to SCLK Rising Edge
t6 5 ns min Data Hold Time after SCLK Rising Edge
t7 5 ns min

1

t

40 ns max

8

CS

to SCLK Hold Time

CS

to DOUT High Impedance

1

Measured with the load circuit of Figure 2.

200µA

TO

OUTPUT

PIN

C

L

50pF

200µAI

Figure 2. Load Circ uit for Dat a Access Time and Bus Relinquish Time

I

OL

1.6V

OH

02884-0-002

Rev. PrE | Page 4 of 14

Preliminary Technical Data ADT7302

ABSOLUTE MAXIMUM RATINGS

Table 3. ADT7302 Stress Ratings

Parameter Rating

VDD to GND −0.3 V to +7 V
Digital Input Voltage to GND −0.3 V to VDD + 0.3 V
Digital Output Voltage to GND −0.3 V to VDD + 0.3 V
Operating Temperature Range −40°C to +125°C
Storage Temperature Range −65°C to +150°C
Junction Temperature 150°C
6-Lead SOT-23 (RJ-6)

Power Dissipation1 W

MAX

= (T

JMAX

- T

2

A

)/θJA

Thermal Impedance

θJA, Junction-to-Ambient (Still Air) 190.4°C/W

8-Lead MSOP (RM-8)

Power Dissipation1 W

MAX

= (T

JMAX

- T

A

2

)/θJA

Thermal Impedance3

θJA, Junction-to-Ambient (Still Air) 205.9°C/W
θJC, Junction-to-Case 43.74°C/W

IR Reflow Soldering

Peak Temperature +220°C (−0/+5°C)
Time at Peak Temperature 10 s to 20 s
Ramp-up Rate 2°C/s to 3°C/s
Ramp-down Rate −6°C/sec

1

Values relate to the package being used on a standard 2-layer PCB. Reference

Figure 3 for a plot of maximum power dissipation versus ambient
temperature (T

2

TA = ambient temperature

3

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

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

).

A

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

1.2

1.0

0.8

0.6

0.4

0.2

MAXIMUM POWER DISSIPATION (W)

0

–10

–20

–30

–40

0

Figure 3. Plot of Maximum Power Dissipation vs. Temperature

SOT-23

MSOP

50

40

30

20

10

TEMPERATURE (°C)

150

140

130

120

110

100

90

80

70

60

02884-0-003

ESD CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the
human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.

Rev. PrE | Page 5 of 14