Rainbow Electronics LM92 User Manual

Lm92, General description, Features

LM92

0.33˚C Accurate, 12-Bit + Sign Temperature Sensor and

Thermal Window Comparator with Two-Wire Interface

General Description

The LM92 is a digital temperature sensor and thermal win-
dow comparator with an I

™

Serial Bus interface and an

accuracy of

0.33˚C. The window-comparator architecture

of the LM92 eases the design of temperature control sys-
tems. The open-drain Interrupt (INT) output becomes active
whenever temperature goes outside a programmable win-
dow,

while

separate

Critical

Temperature

Alarm

(T_CRIT_A) output becomes active when the temperature
exceeds a programmable critical limit. The INT output can
operate in either a comparator or event mode, while the
T_CRIT_A output operates in comparator mode only.

The host can program both the upper and lower limits of the
window as well as the critical temperature limit. Program-
mable hysterisis as well as a fault queue are available to
minimize false tripping. Two pins (A0, A1) are available for
address selection. The sensor powers up with default thresh-
olds of 2˚C T

HYST

, 10˚C T

LOW

, 64˚C T

HIGH

, and 80˚C

T_CRIT.

The LM92’s 2.7V to 5.5V supply voltage range, Serial Bus in-
terface, 12-bit + sign output, and full-scale range of over
128˚C make it ideal for a wide range of applications. These
include thermal management and protection applications in
personal computers, electronic test equipment, office elec-
tronics, automotive, medical and HVAC applications.

Features

Window comparison simplifies design of ACPI
compatible temperature monitoring and control.

Serial Bus interface

Separate open-drain outputs for Interrupt and Critical
Temperature shutdown

Shutdown mode to minimize power consumption

Up to 4 LM92s can be connected to a single bus

12-bit + sign output

Operation up to 150˚C

Key Specifications

Supply Voltage

2.7V to 5.5V

Supply Current

operating

350µA (typ)

625µA (max)

shutdown

5µA (typ)

Temperature

30˚C

0.33˚C(max)

Accuracy

10˚C to 50˚C

0.50˚C(max)

−10˚C to 85˚C

1.0˚C(max)

125˚C

1.25˚C(max)

−25˚C to 150˚C

1.5˚C(max)

Linearity

0.5˚C(max)

Resolution

0.0625˚C

Applications

HVAC

Medical Electronics

Electronic Test Equipment

System Thermal Management

Personal Computers

Office Electronics

Automotive

Simplified Block Diagram

I2C

is a registered trademark of Philips Corporation.

DS101051-1

March 2000

LM92

0.33˚C

Accurate,

12-Bit

Sign

emperature

Sensor

and

Thermal

indow

Comparator

with

wo-W

ire

Interface

DS101051