Dual Channel Temperature Sensor

and Over Temperature Alarm

ADT7483A

Rev. 0

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

responsibilityis assumedbyAnalogDevicesforitsuse,norforanyinfringements of patents or other

rightsofthirdpartiesthatmayresultfromitsuse.Specificationssubjecttochangewithoutnotice.No

license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.

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

Tel: 781.329.4700

www.analog.com

Fax: 781.461.3113

©2005 Analog Devices, Inc. All rights reserved.

FEATURES

1 local and 2 remote temperature sensors

0.25°C resolution/1°C accuracy on remote channels

1°C resolution/1°C accuracy on local channel

Extended, switchable temperature measurement range

0°C to 127°C (default) or –64°C to +191°C

2-wire SMBus serial interface with SMBus alert support

Programmable over/under temperature limits

Offset registers for system calibration

Up to 2 overtemperature fail-safe THERM outputs

Small 16-lead QSOP package

240 μA operating current, 5 μA standby current

APPLICATIONS

Desktop and notebook computers

Industrial controllers

Smart batteries

Automotive

Embedded systems

Burn-in applications

Instrumentation

GENERAL DESCRIPTION

The ADT7483A1 is a three-channel digital thermometer and

under/over temperature alarm, intended for use in PCs and

thermal management systems. It can measure the temperature

in two remote locations, for example, the remote thermal diode

in a CPU or GPU, or a discrete diode connected transistor. It can

also measure its own ambient temperature. The temperature of the

remote thermal diode and ambient temperature can be accurately

measured to ±1°C. The temperature measurement range defaults to

0°C to 127°C, compatible with ADM1032, but can be switched

to a wider measurement range, from −64°C to +191°C.

The ADT7483A communicates over a 2-wire serial interface

compatible with system management bus (SMBus) standards.

The SMBus address is set by the ADD0 and ADD1 pins. As

many as nine different SMBus addresses are possible.

An ALERT output signals when the on-chip or remote

temperature is outside the programmed limits. The THERM

output is a comparator output that allows, for example, on/off

control of a cooling fan. The ALERT output can be reconfigured

as a second THERM output, if required.

FUNCTIONAL BLOCK DIAGRAM

11-BIT A-TO-D

CONVERTER

RUN/STANDBY

BUSY

REMOTE 1 AND 2 TEMP

OFFSET REGISTERS

STATUS REGISTERS

INTERRUPT

MASKING

CONFIGURATION

REGISTERS

REMOTE 1 AND 2 TEMP

HIGH LIMIT REGISTERS

REMOTE 1 AND 2 TEMP

LOW LIMIT REGISTERS

REMOTE 1 AND 2 TEMP

THERM LIMIT REGISTER

LOCAL TEMPERATURE

HIGH LIMIT REGISTER

LOCAL TEMPERATURE

LOW LIMIT REGISTER

LOCAL TEMPERATURE

THERM LIMIT REGISTER

ONE-SHOT

REGISTER

ADDRESS POINTER

REGISTER

CONVERSION RATE

REGISTER

REMOTE 1 AND 2 TEMP

VALUE REGISTERS

LOCAL TEMPERATURE

VALUE REGISTER

ON-CHIP TEMP

SENSOR

ANALOG

MUX

EXTERNAL DIODES OPEN-CIRCUIT

SMBus INTERFACE

ADT7483A

12

11

4

3

15

5

2

6

14

GND

SDATA SCLK

THERM

13

D1+

D1–

D2+

D2–

ALERT/THERM2

1

16

ADD0

ADD1

Figure 1.