REV.0
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a
ADM1032
*
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 www.analog.com
Fax: 781/326-8703 © Analog Devices, Inc., 2001
H115501H11543C 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
V
DD
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
DIGITAL MUX
DIGITAL MUX
STATUS REGISTER
SMBUS INTERFACE
REMOTE OFFSET
REGISTER
FEATURES
On-Chip and Remote Temperature Sensing
Offset Registers for System Calibration
0.125H11543C Resolution/1H11543C Accuracy on Remote Channel
1H11543C Resolution/3H11543C 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 H9262A Operating Current
5.5 H9262A 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.