LM61

2.7V, SOT-23 or TO-92 Temperature Sensor

General Description

The LM61 is a precision integrated-circuit temperature sen-

sor that can sense a −30˚C to +100˚C temperature range

while operating from a single +2.7V supply. The LM61’s out-

put voltage is linearly proportional to Celsius (Centigrade)

temperature (+10 mV/˚C) and has a DC offset of +600 mV.

The offset allows reading negative temperatures without the

need for a negative supply. The nominal output voltage of the

LM61 ranges from +300 mV to +1600 mV for a −30˚C to

+100˚C temperature range. The LM61 is calibrated to pro-

over the full −25˚C to +85˚C temperature range.

The LM61’s linear output, +600 mV offset, and factory cali-

bration simplify external circuitry required in a single supply

environment where reading negative temperatures is re-

quired. Because the LM61’s quiescent current is less than

125 µA, self-heating is limited to a very low 0.2˚C in still air.

Shutdown capability for the LM61 is intrinsic because its in-

herent low power consumption allows it to be powered di-

rectly from the output of many logic gates.

Features

n Calibrated linear scale factor of +10 mV/˚C

n Rated for full −30˚ to +100˚C range

n Suitable for remote applications

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

Key Specifications

n Accuracy at 25˚C

(max)

n Accuracy for −30˚C to +100˚C

n Accuracy for −25˚C to +85˚C

n Temperature Slope

+10 mV/˚C

n Power Supply Voltage Range

+2.7V to +10V

125 µA (max)

n Nonlinearity

n Output Impedance

800

Ω (max)

Typical Application

DS012897-2

V

Temperature (T)

Typical V

O

+100˚C

+1600 mV

+85˚C

+1450 mV

+25˚C

+850 mV

0˚C

+600 mV

−25˚C

+350 mV

−30˚C

+300 mV

FIGURE 1. Full-Range Centigrade Temperature Sensor (−30˚C to +100˚C)

Operating from a Single Li-Ion Battery Cell

June 1999

© 1999 National Semiconductor Corporation

DS012897

www.national.com