ADM1021ARQ データシートの表示（PDF） - Analog Devices

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ADM1021ARQ

Low Cost Microprocessor System Temperature Monitor

Analog Devices 

a

Low Cost Microprocessor

System Temperature Monitor

ADM1021

FEATURES

Improved Replacement for MAX1617

On-Chip and Remote Temperature Sensing

No Calibration Necessary

1؇C Accuracy for On-Chip Sensor

3؇C Accuracy for Remote Sensor

Programmable Over/Under Temperature Limits

Programmable Conversion Rate

2-Wire SMBus Serial Interface

Supports System Management Bus (SMBus™) Alert

70 ␮A Max Operating Current

3 ␮A Standby Current

3 V to 5.5 V Supply

Small 16-Lead QSOP Package

APPLICATIONS

Desktop Computers

Notebook Computers

Smart Batteries

Industrial Controllers

Telecomms Equipment

Instrumentation

PRODUCT DESCRIPTION

The ADM1021 is a two-channel digital thermometer and under/

over temperature alarm, intended for use in personal computers

and other systems requiring thermal monitoring and manage-

ment. The device can measure the temperature of a micropro-

cessor using a diode-connected PNP transistor, which may be

provided on-chip in the case of the Pentium® II or similar pro-

cessors, or can be a low cost discrete NPN/PNP device such as

the 2N3904/2N3906. 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 chan-

nel measures the output of an on-chip temperature sensor, to

monitor the temperature of the device and its environment.

The ADM1021 communicates over a two-wire serial interface

compatible with SMBus standards. Under and over temperature

limits can be programmed into the devices over the serial bus,

and an ALERT output signals when the on-chip or remote

temperature is out of range. This output can be used as an inter-

rupt, or as an SMBus alert.

FUNCTIONAL BLOCK DIAGRAM

ON-CHIP TEMP.

SENSOR

LOCAL TEMPERATURE

VALUE REGISTER

D+

D–

ANALOG MUX

8-BIT A-TO-D

CONVERTER

BUSY RUN/STANDBY

REMOTE TEMPERATURE

VALUE REGISTER

EXTERNAL DIODE OPEN-CIRCUIT

LOCAL TEMPERATURE

LOW LIMIT COMPARATOR

LOCAL TEMPERATURE

HIGH LIMIT COMPARATOR

REMOTE TEMPERATURE

LOW LIMIT COMPARATOR

REMOTE TEMPERATURE

HIGH LIMIT COMPARATOR

STATUS REGISTER

ADDRESS POINTER

REGISTER

ONE-SHOT

REGISTER

CONVERSION RATE

REGISTER

LOCAL TEMPERATURE

LOW LIMIT REGISTER

LOCAL TEMPERATURE

HIGH LIMIT REGISTER

REMOTE TEMPERATURE

LOW LIMIT REGISTER

REMOTE TEMPERATURE

HIGH LIMIT REGISTER

CONFIGURATION

REGISTER

INTERRUPT

MASKING

STBY

ALERT

ADM1021

SMBUS INTERFACE

TEST VDD NC GND GND NC NC

TEST

SDATA

SCLK

ADD0

ADD1

SMBus is a trademark and Pentium is a registered trademark of Intel Corporation.

REV. 0

Information furnished by Analog Devices is believed to be accurate and

reliable. However, no responsibility is assumed by Analog Devices for its

use, nor for any infringements of patents or other rights of third parties

which may result from its use. No license is granted by implication or

otherwise under any patent or patent rights of Analog Devices.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781/329-4700 World Wide Web Site: http://www.analog.com

Fax: 781/326-8703

© Analog Devices, Inc., 1998

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