Rainbow-electronics LM45 User Manual download pdf

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-

cies of

2˚C at room temperature and

3˚C over a full −20 to

+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

3˚C accuracy guaranteed

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 Nonlinearity only

0.8˚C max over temp

n Low impedance output, 20Ω 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

Choose R

=−V

/50 µA

OUT

= (10 mV/˚C x Temp ˚C)

OUT

= +1,000 mV at +100˚C

= +250 mV at +25˚C

= −200 mV at −20˚C

FIGURE 2. Full-Range Centigrade

Temperature Sensor (−20˚C to +100˚C)

August 1999

LM45 SOT-23 Precision Centigrade Temperature Sensors

1 2 3 4 5 6 7 8 9

Summary of Contents

Page 1 - Typical Applications

LM45SOT-23 Precision Centigrade Temperature SensorsGeneral DescriptionThe LM45 series are precision integrated-circuit temperaturesensors, whose outpu

Page 2 - Electrical Characteristics

Absolute Maximum Ratings (Note 1)Supply Voltage +12V to −0.2VOutput Voltage +VS+ 0.6V to−1.0VOutput Current 10 mAStorage Temperature −65˚C to +150˚CLe

Page 3 - Figure 1

Typical Performance Characteristics To generate these curves the LM45 was mounted to a printedcircuit board as shown inFigure 3.Thermal ResistanceJunc

Page 4

Typical Performance Characteristics To generate these curves the LM45 was mounted to a printedcircuit board as shown inFigure 3. (Continued)Applicatio

Page 5

Typical ApplicationsCAPACITIVE LOADSLike most micropower circuits, the LM45 has a limited abilityto drive heavy capacitive loads. The LM45 by itself i

Page 6 - DS011754-19

Typical Applications (Continued)DS011754-17FIGURE 10. Expanded Scale Thermometer(50˚ to 80˚ Fahrenheit, for Example Shown)DS011754-18FIGURE 11. Temper

Page 7 - (Continued)

Typical Applications (Continued)DS011754-20* =1% or 2% film resistor-Trim RBfor VB=3.075V-Trim RCfor VC=1.955V-Trim RAfor VA=0.075V + 100mV/˚C x Tambi

Page 8 - Block Diagram

Block DiagramDS011754-22LM45www.national.com 8

Page 9 - NS Package Number MA03B

Physical Dimensions inches (millimeters) unless otherwise notedLIFE SUPPORT POLICYNATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENT

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Rainbow-electronics LM45 User Manual

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