LM20

2.4V, 10µA, SC70, micro SMD Temperature Sensor

General Description

The

LM20

is

a

precision

analog

output

CMOS

integrated-circuit temperature sensor that operates over a

−55˚C to +130˚C temperature range. The power supply op-

erating range is +2.4 V to +5.5 V. The transfer function of

LM20 is predominately linear, yet has a slight predictable

parabolic curvature. The accuracy of the LM20 when speci-

temperature of +30˚C. The temperature error increases lin-

range extremes. The temperature range is affected by the

power supply voltage. At a power supply voltage of 2.7 V to

5.5 V the temperature range extremes are +130˚C and

−55˚C. Decreasing the power supply voltage to 2.4 V

changes the negative extreme to −30˚C, while the positive

remains at +130˚C.

The LM20’s quiescent current is less than 10 µA. Therefore,

self-heating is less than 0.02˚C in still air. Shutdown capabil-

ity for the LM20 is intrinsic because its inherent low power

consumption allows it to be powered directly from the output

of many logic gates or does not necessitate shutdown at all.

Applications

n Cellular Phones

n Computers

n Power Supply Modules

n Battery Management

n FAX Machines

n Printers

n HVAC

n Disk Drives

n Appliances

Features

n Rated for full −55˚C to +130˚C range

n Available in an SC70 and a micro SMD package

n Predictable curvature error

n Suitable for remote applications

Key Specifications

n Accuracy at +30˚C

n Accuracy at +130˚C & −55˚C

n Power Supply Voltage Range

+2.4V to +5.5V

n Current Drain

10 µA (max)

n Nonlinearity

n Output Impedance

160

Ω (max)

n Load Regulation

−2.5 mV (max)

Typical Application

DS100908-2

V

or

where:

Output Voltage vs Temperature

DS100908-24

Full-Range Celsius (Centigrade) Temperature Sensor (−55˚C to +130˚C)

Operating from a Single Li-Ion Battery Cell

October 1999

© 1999 National Semiconductor Corporation

DS100908

www.national.com