PRELIMINARY TECHNICAL DATA
± ±1° ꢀLoca cꢁn ꢂReLꢃR
a
SysꢃReTRepRrcꢃurRMLꢁiꢃLr
ADM±032*
FEATURES
PRODUCT DESCRIPTION
On-chip and remote temperature sensing
Offset Registers for System Calibration
1oC Accuracy and Resolution on Local Channel
0.125oC Resolution/1oC Accuracy on Remote Channel
Fast (up to 32 Conversions/second)
ProgrammableOver/UnderTemperatureLimits
Programmable Fault Queue
ProgrammableTHERMLimits
ProgrammableTHERMHysteresis
2-wire SMBus serial interface
Supports SMBus Alert
160µA Max Operating Current
3µA standby current
3V to 5.5V supply
Small 8-pin SO and uSO package
Optimized for PentiumIII - Allows Reduced
Guardbanding
The ADM1032 is an ACPI compliant two-channel digital
thermometer and under/over temperature alarm, intended
for use in personal computers and thermal management
systems. Optimized for the Pentium III , 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 in the case of
the Pentium III or similar processors, 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 measures 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 in-
terface compatible with System Management Bus
(SMBusTM) 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.
Applications
DesktopComputers
NotebookComputers
SmartBatteries
IndustrialControllers
TelecommsEquipment
Instrumentation
FUNCTIONAL BLOCK DIAGRAM
ADDRESS POINTER
REGISTER
CONVERSION RATE
REGISTER
ON-CHIP TEMP.
SENSOR
LOCAL TEMPERATURE
VALUE REGISTER
LOCAL TEMPERATURE
LOW LIMIT REGISTER
LOCAL TEMPERATURE
HIGH LIMIT REGISTER
D+
D-
2
A TO D
CONVERTER
LIMIT
COMPARATORS
ANALOG MUX
REMOTE TEMPERATURE
LOW LIMIT REGISTER
3
BUSY
RUN/STANDBY
REMOTE TEMPERATURE
HIGH LIMIT REGISTER
REMOTE TEMPERATURE
VALUE REGISTER
LOCAL THERM LIMIT
REGISTER
EXTERNAL THERM LIMIT
INTERNAL THERM LIMIT
REGISTER
REGISTER
CONFIGURATION
REGISTER
EXTERNAL DIODE OPEN-
CIRCUIT
INTERRUPT
MASKING
STATUS REGISTER
ALERT
THERM
6
4
SMBUS INTERFACE
ADM1032
1
5
7
8
V
GND
DD
SDATA SCLK
REV.PrL 03/2001
PentiumIII is a registered trademark of Intel Corporation
*Patents Pending
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: 617/329-4700
Fax: 617/326-8703
World Wide Web Site: http://www.analog.com
© Analog Devices, Inc., 1997