LM35 - National Semiconductor

LM35 Precision Centigrade Temperature Sensors

The LM35 series are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Celsius (Centigrade) temperature. The LM35 thus has an advantage over linear temperature sensors calibrated in ˚ Kelvin, as the user is not required to subtract a large constant voltage from its output to obtain convenient Centigrade sca.

Features

n n n n n n n n n n n Calibrated directly in ˚ Celsius (Centigrade) Linear + 10.0 mV/˚C scale factor 0.5˚C accuracy guaranteeable (at +25˚C) Rated for full −55˚ to +150˚C range Suitable for remote applications Low cost due to wafer-level trimming Operates from 4 to 30 volts Less than 60 µA current drain Low self-heating, 0.08˚C in still air Nonlinearity only ± 1⁄4˚C typical Low impedance output, 0.1 Ω for 1 mA load Typical Applications DS005516-4 DS005516-3 FIGURE 1. Basic Centigrade Temperature Sensor (+2˚C to +150˚C) Choose R1 = −VS/50 µA V OUT = +1,500 mV at +150˚C = +250 mV at +25˚C = .