REV. 0

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© Analog Devices, Inc., 2001

1 C Remote and Local

System Temperature Monitor

FUNCTIONAL BLOCK DIAGRAM

ON-CHIP

TEMPERATURE

SENSOR

A-TO-D

CONVERTER

BUSY

RUN/STANDBY

EXTERNAL DIODE OPEN-CIRCUIT

ADDRESS POINTER

REGISTER

CONVERSION RATE

REGISTER

REMOTE TEMPERATURE

HIGH-LIMIT REGISTER

CONFIGURATION

REGISTER

INTERRUPT

MASKING

LIMIT

COMPARATOR

REMOTE TEMPERATURE

VALUE REGISTER

LOCAL TEMPERATURE

VALUE REGISTER

GND

SDATA

SCLK

THERM

ALERT

D+

D–

REMOTE TEMPERATURE

LOW-LIMIT REGISTER

LOCAL TEMPERATURE

HIGH-LIMIT REGISTER

LOCAL TEMPERATURE

LOW-LIMIT REGISTER

ANALOG

MUX

ADM1032

LOCAL THERM LIMIT

REGISTER

EXTERNAL THERM LIMIT

REGISTER

STATUS REGISTER

SMBUS INTERFACE

REMOTE OFFSET

REGISTER

FEATURES

On-Chip and Remote Temperature Sensing

Offset Registers for System Calibration

0.125 C Resolution/1 C Accuracy on Remote Channel

1 C Resolution/3 C Accuracy on Local Channel

Fast (Up to 64 Measurements per Second)

2-Wire SMBus Serial Interface

Supports SMBus Alert

Programmable Over/Under Temperature Limits

Programmable Fault Queue

Over-Temperature Fail-Safe

THERM Output

Programmable

THERM Limits

Programmable

THERM Hysteresis

170

A Operating Current

5.5

A Standby Current

3 V to 5.5 V Supply

Small 8-Lead SO and Micro_SO Package

APPLICATIONS

Desktop Computers

Notebook Computers

Smart Batteries

Industrial Controllers

Telecomms Equipment

Instrumentation

Embedded Systems

Pentium is a registered trademark of Intel Corporation.

*Patents 5,982,221, 6,097,239, 6,133,753, 6,169,442, 5,867,012.

PRODUCT DESCRIPTION

The ADM1032 is a dual-channel digital thermometer and

under/over temperature alarm, intended for use in personal

computers and thermal management systems. The higher 1

°C

accuracy offered allows systems designers to safely reduce

temperature guardbanding and increase system performance.

The device can measure the temperature of a microprocessor

using a diode-connected NPN or PNP transistor, which may be

provided on-chip or can be a low-cost discrete device such as

the 2N3906. A novel measurement technique cancels out the

absolute value of the transistor’s base emitter voltage, so that no

calibration is required. The second measurement channel mea-

sures the output of an on-chip temperature sensor, to monitor

the temperature of the device and its environment.

The ADM1032 communicates over a two-wire serial interface

compatible with System Management Bus (SMBus) standards.

Under and over temperature limits can be programmed into the

device over the serial bus, and an

ALERT output signals when

the on-chip or remote temperature measurement is out of range.

This output can be used as an interrupt, or as an SMBus alert.

The

THERM output is a comparator output that allows CPU

clock throttling or on/off control of a cooling fan.