LM34 Precision Fahrenheit Temperature Sensors
July 1999
LM34
Precision Fahrenheit Temperature Sensors
General Description
The LM34 series are precision integrated-circuit temperature
sensors, whose output voltage is linearly proportional to the
Fahrenheit temperature. The LM34 thus has an advantage
over linear temperature sensors calibrated in degrees
Kelvin, as the user is not required to subtract a large con-
stant voltage from its output to obtain convenient Fahrenheit
scaling. The LM34 does not require any external calibration
or trimming to provide typical accuracies of
±
1
⁄
2
˚F at room
temperature and
±
1
1
⁄
2
˚F over a full −50 to +300˚F tempera-
ture range. Low cost is assured by trimming and calibration
at the wafer level. The LM34’s low output impedance, 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 75 µA from its supply, it has very low
self-heating, less than 0.2˚F in still air. The LM34 is rated to
operate over a −50˚ to +300˚F temperature range, while the
LM34C is rated for a −40˚ to +230˚F range (0˚F with im-
proved accuracy). The LM34 series is available packaged in
hermetic TO-46 transistor packages, while the LM34C,
LM34CA and LM34D are also available in the plastic TO-92
transistor package. The LM34D is also available in an 8-lead
surface mount small outline package. The LM34 is a comple-
ment to the LM35 (Centigrade) temperature sensor.
Features
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Calibrated directly in degrees Fahrenheit
Linear +10.0 mV/˚F scale factor
1.0˚F accuracy guaranteed (at +77˚F)
Rated for full −50˚ to +300˚F range
Suitable for remote applications
Low cost due to wafer-level trimming
Operates from 5 to 30 volts
Less than 90 µA current drain
Low self-heating, 0.18˚F in still air
Nonlinearity only
±
0.5˚F typical
Low-impedance output, 0.4Ω for 1 mA load
Connection Diagrams
TO-46
Metal Can Package
(Note 1)
TO-92
Plastic Package
SO-8
Small Outline
Molded Package
DS006685-1
DS006685-2
Order Numbers LM34H,
LM34AH, LM34CH,
LM34CAH or LM34DH
See NS Package
Number H03H
Order Number LM34CZ,
LM34CAZ or LM34DZ
See NS Package
Number Z03A
DS006685-20
N.C. = No Connection
Top View
Order Number LM34DM
See NS Package Number M08A
Note 1:
Case is connected to negative pin (GND).
TRI-STATE
®
is a registered trademark of National Semiconductor Corporation.
© 1999 National Semiconductor Corporation
DS006685
www.national.com
NSC [ NATIONAL SEMICONDUCTOR ]
