LM77

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SNIS103F – JUNE 1999 – REVISED MARCH 2013

LM77 9-Bit + Sign Digital Temperature Sensor and Thermal Window Comparator with

Two-Wire Interface

Check for Samples: LM77

1

FEATURES

DESCRIPTION

The LM77 is a digital temperature sensor and thermal

2

•

Window Comparison Simplifies Design of

ACPI Compatible Temperature Monitoring and

The window-comparator architecture of the LM77

Control.

eases the design of temperature control systems

•

Serial Bus Interface

conforming to the ACPI (Advanced Configuration and

Power

Interface)

specification

for

personal

•

Separate Open-Drain Outputs for Interrupt and

computers. The open-drain Interrupt (INT) output

Critical Temperature Shutdown

becomes active whenever temperature goes outside

•

Shutdown Mode to Minimize Power

a programmable window, while a separate Critical

Consumption

Temperature Alarm (T_CRIT_A) output becomes

•

Up to 4 LM77s Can be Connected to a Single

active

when

the

temperature

exceeds

a

Bus

programmable critical limit. The INT output can

operate in either a comparator or event mode, while

•

9-bit + Sign Output; Full-Scale Reading of Over

the T_CRIT_A output operates in comparator mode

128°C

only.

•

SOIC and VSSOP 8-lead Packages

The host can program both the upper and lower limits

of the window as well as the critical temperature limit.

APPLICATIONS

Programmable hysterisis as well as a fault queue are

•

System Thermal Management

available to minimize false tripping. Two pins (A0, A1)

are available for address selection. The sensor

•

Personal Computers

•

Office Electronics

•

Electronic Test Equipment

The LM77's 3.0V to 5.5V supply voltage range, Serial

•

Automotive

Bus interface, 9-bit + sign output, and full-scale range

•

HVAC

of over 128°C make it ideal for a wide range of

applications. These include thermal management and

KEY SPECIFICATIONS

protection

applications

in

personal

computers,

electronic

test

equipment,

office

electronics,

•

Supply Voltage 3.0V to 5.5V

automotive, and HVAC applications.

•

Supply Current

–

Operating

–

250

μA (typ)

–

500

μA (max)

–

Shutdown

–

5

μA (typ)

•

Temperature Accuracy

–

−10°C to 65°C, ±1.5°C(max)

–

−25°C to 100°C, ±2°C(max)

–

−55°C to 125°C, ±3°C(max)

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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2

All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Copyright © 1999–2013, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.