LM135/LM235/LM335, LM135A/LM235A/LM335A Precision Temperature Sensors
November 2000
LM135/LM235/LM335, LM135A/LM235A/LM335A
Precision Temperature Sensors
General Description
The LM135 series are precision, easily-calibrated, integrated
circuit temperature sensors. Operating as a 2-terminal zener,
the LM135 has a breakdown voltage directly proportional to
absolute temperature at +10 mV/˚K. With less than 1Ω dy-
namic impedance the device operates over a current range
of 400 µA to 5 mA with virtually no change in performance.
When calibrated at 25˚C the LM135 has typically less than
1˚C error over a 100˚C temperature range. Unlike other
sensors the LM135 has a linear output.
Applications for the LM135 include almost any type of tem-
perature sensing over a −55˚C to +150˚C temperature
range. The low impedance and linear output make interfac-
ing to readout or control circuitry especially easy.
The LM135 operates over a −55˚C to +150˚C temperature
range while the LM235 operates over a −40˚C to +125˚C
temperature range. The LM335 operates from −40˚C to
+100˚C. The LM135/LM235/LM335 are available packaged
in hermetic TO-46 transistor packages while the LM335 is
also available in plastic TO-92 packages.
Features
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Directly calibrated in ˚Kelvin
1˚C initial accuracy available
Operates from 400 µA to 5 mA
Less than 1Ω dynamic impedance
Easily calibrated
Wide operating temperature range
200˚C overrange
Low cost
Schematic Diagram
DS005698-1
© 2000 National Semiconductor Corporation
DS005698
www.national.com