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LM35 Datasheet, PDF (1/13 Pages) National Semiconductor (TI) – Precision Centigrade Temperature Sensors | |||
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November 2000
LM35
Precision Centigrade Temperature Sensors
General Description
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
Ë Kelvin, as the user is not required to subtract a large
constant voltage from its output to obtain convenient Centi-
grade scaling. The LM35 does not require any external
calibration or trimming to provide typical accuracies of ±1â4ËC
at room temperature and ±3â4ËC over a full â55 to +150ËC
temperature range. Low cost is assured by trimming and
calibration at the wafer level. The LM35âs low output imped-
ance, linear output, and precise inherent calibration make
interfacing to readout or control circuitry especially easy. It
can be used with single power supplies, or with plus and
minus supplies. As it draws only 60 µA from its supply, it has
very low self-heating, less than 0.1ËC in still air. The LM35 is
rated to operate over a â55Ë to +150ËC temperature range,
while the LM35C is rated for a â40Ë to +110ËC range (â10Ë
with improved accuracy). The LM35 series is available pack-
aged in hermetic TO-46 transistor packages, while the
LM35C, LM35CA, and LM35D are also available in the
plastic TO-92 transistor package. The LM35D is also avail-
able in an 8-lead surface mount small outline package and a
plastic TO-220 package.
Features
n Calibrated directly in Ë Celsius (Centigrade)
n Linear + 10.0 mV/ËC scale factor
n 0.5ËC accuracy guaranteeable (at +25ËC)
n Rated for full â55Ë to +150ËC range
n Suitable for remote applications
n Low cost due to wafer-level trimming
n Operates from 4 to 30 volts
n Less than 60 µA current drain
n Low self-heating, 0.08ËC in still air
n Nonlinearity only ±1â4ËC typical
n Low impedance output, 0.1 ⦠for 1 mA load
Typical Applications
DS005516-3
FIGURE 1. Basic Centigrade Temperature Sensor
(+2ËC to +150ËC)
DS005516-4
Choose R1 = âVS/50 µA
V OUT=+1,500 mV at +150ËC
= +250 mV at +25ËC
= â550 mV at â55ËC
FIGURE 2. Full-Range Centigrade Temperature Sensor
© 2000 National Semiconductor Corporation DS005516
www.national.com
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