LM45

SOT-23 Precision Centigrade Temperature Sensors

General Description

The LM45 series are precision integrated-circuit temperature

sensors, whose output voltage is linearly proportional to the

Celsius (Centigrade) temperature. The LM45 does not re-

quire any external calibration or trimming to provide accura-

+100˚C temperature range. Low cost is assured by trimming

and calibration at the wafer level. The LM45’s low output im-

pedance, linear output, and precise inherent calibration

make interfacing to readout or control circuitry especially

easy. It can be used with a single power supply, or with plus

and minus supplies. As it draws only 120 µA from its supply,

it has very low self-heating, less than 0.2˚C in still air. The

LM45 is rated to operate over a −20˚ to +100˚C temperature

range.

Applications

n Battery Management

n FAX Machines

n Printers

n Portable Medical Instruments

n HVAC

n Power Supply Modules

n Disk Drives

n Computers

n Automotive

Features

n Calibrated directly in ˚ Celsius (Centigrade)

n Linear + 10.0 mV/˚C scale factor

n Rated for full −20˚ to +100˚C range

n Suitable for remote applications

n Low cost due to wafer-level trimming

n Operates from 4.0V to 10V

n Less than 120 µA current drain

n Low self-heating, 0.20˚C in still air

n Low impedance output, 20

Ω for 1 mA load

Connection Diagram

SOT-23

Order

Device

Number

Marking

Supplied As

LM45BIM3

T4B

1000 Units on Tape and Reel

LM45BIM3X

T4B

3000 Units on Tape and Reel

LM45CIM3

T4C

1000 Units on Tape and Reel

LM45CIM3X

T4C

3000 Units on Tape and Reel

Typical Applications

SOT-23

DS011754-1

Top View

See NS Package Number MA03B

DS011754-3

FIGURE 1. Basic Centigrade Temperature

Sensor (+2.5˚C to +100˚C)

DS011754-4

= +250 mV at +25˚C

= −200 mV at −20˚C

FIGURE 2. Full-Range Centigrade

Temperature Sensor (−20˚C to +100˚C)

July 1999

© 1999 National Semiconductor Corporation

DS011754

www.national.com