Precision Temperature Sensors
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 sen-
sors 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.
n Directly calibrated in ˚Kelvin
n 1˚C initial accuracy available
n Operates from 400 µA to 5 mA
n Less than 1Ω dynamic impedance
n Easily calibrated
n Wide operating temperature range
n 200˚C overrange
n Low cost
© 1999 National Semiconductor Corporation DS005698