Rainbow Electronics LM32 - Manual

LM32
Dual Thermal Diode Temperature Sensor with
SensorPath
™ Bus
General Description
The LM32 is a digital temperature sensor that measures 3
temperature zones and has a single-wire interface compat-
ible with National Semiconductor’s SensorPath bus. Sensor-
Path data is pulse width encoded, thereby allowing the LM32
to be easily connected to many general purpose micro-
controllers. Several National Semiconductor Super I/O prod-
ucts include a fully integrated SensorPath master, that when
connected to an LM32 can realize a hardware monitor func-
tion that includes limit checking for measured values, au-
tonomous fan speed control and many other functions.
The LM32 measures the temperature of its own die as well
as two external devices such as a processor thermal diode
or a diode connected transistor. The LM32 can resolve tem-
peratures up to 255˚C and down to -256˚C. The operating
temperature range of the LM32 is 0˚C to +125˚C. The ad-
dress programming pin allows two LM32s to be placed on
one SensorPath bus.
Features
n SensorPath Interface
— 2 hardware programmable addresses
n 2 remote diode temperature sensor zones
n Internal local temperature zone
n 0.5 ˚C resolution
n Measures temperatures up to 140 ˚C
n 14-lead TSSOP package
Key Specifications
n Temperature Sensor Accuracy ± 3 ˚C (max)
n Temperature Range:
— LM32 junction 0 ˚C to +85 ˚C
— Remote Temp Accuracy 0 ˚C to +100 ˚C
n Power Supply Voltage +3.0 V to +3.6 V
n Average Power Supply Current 0.5 mA (typ)
n Conversion Time (all Channels) 22.5ms to 1456ms
Applications
n Microprocessor based equipment
(Motherboards, Video Cards, Base-stations, Routers,
ATMs, Point of Sale, …)
n Power Supplies
Typical Application
20071101
SensorPath ™ is a trademark of National Semiconductor Corporation
May 2004
LM32
Dual
Thermal
Diode
T
emperature
Sensor
with
SensorPath
™
Bus
© 2004 National Semiconductor Corporation DS200711 www.national.com