LM75

Digital Temperature Sensor and Thermal Watchdog with

Two-Wire Interface

General Description

The LM75 is a temperature sensor, Delta-Sigma analog-to-

digital converter, and digital over-temperature detector with

I

read temperature. The open-drain Overtemperature Shut-

down (O.S.) output becomes active when the temperature

exceeds a programmable limit. This pin can operate in either

“Comparator” or “Interrupt” mode.

The host can program both the temperature alarm threshold

(T

away (T

tents of the LM75’s T

A1, A2) are available for address selection. The sensor

powers up in Comparator mode with default thresholds of

80˚C T

The LM75’s 3.0V to 5.5V supply voltage range, low supply

current and I

applications. These include thermal management and pro-

tection applications in personal computers, electronic test

equipment, and office electronics.

Features

n

SOP-8 and Mini SOP-8 (MSOP) packages save space

n

I

n

Separate open-drain output pin operates as interrupt or

comparator/thermostat output

n

Register readback capability

n

Power up defaults permit stand-alone operation as

thermostat

n

Shutdown mode to minimize power consumption

n

Up to 8 LM75s can be connected to a single bus

n

UL Recognized Component

Key Specifications

3.0V to 5.5V

operating

250 µA (typ)

1 mA (max)

shutdown

4 µA (typ)

−25˚C to 100˚C

−55˚C to 125˚C

Applications

n

System Thermal Management

n

Personal Computers

n

Office Electronics

n

Electronic Test Equipment

Simplified Block Diagram

01265801

October 2005

© 2005 National Semiconductor Corporation

DS012658

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