December 1994
LM34/LM34A/LM34C/LM34CA/LM34D
Precision Fahrenheit Temperature Sensors
General Description
The LM34 series are precision integrated-circuit tempera-
ture sensors, whose output voltage is linearly proportional to
the Fahrenheit temperature. The LM34 thus has an advan-
tage 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 Fahren-
heit scaling. The LM34 does not require any external cali-
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 complement to the LM35 (Centigrade) tem-
perature sensor.
Features
Y
g
bration or trimming to provide typical accuracies of (/2 F at
b
§
room temperature and 1(/2 F over a full 50 to 300 F
Calibrated directly in degrees Fahrenheit
a
g
§
§
Y
a
Linear 10.0 mV/ F scale factor
1.0 F accuracy guaranteed (at 77 F)
§
temperature range. Low cost is assured by trimming and
calibration at the wafer level. The LM34’s 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 75 mA from its supply, it has
Y
Y
Y
Y
Y
Y
Y
Y
Y
a
§
§
b
a
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
very low self-heating, less than 0.2 F in still air. The LM34 is
§
50 to
Less than 90 mA current drain
b
a
range, while the LM34C is rated for a 40 to
rated to operate over
a
300 F temperature
a
230 F
§
§
Low self-heating, 0.18 F in still air
§
b
range (0 F with improved accuracy). The LM34 series is
§
§
g
Nonlinearity only 0.5 F typical
§
§
available packaged in hermetic TO-46 transistor packages,
Low-impedance output, 0.4X for 1 mA load
Connection Diagrams
TO-46
Metal Can Package*
TO-92
Plastic Package
SO-8
Small Outline Molded Package
TL/H/6685–1
TL/H/6685–2
*Case is connected to negative pin (GND).
Order Numbers LM34H, LM34AH,
LM34CH, LM34CAH or LM34DH
See NS Package Number H03H
Order Number LM34CZ,
LM34CAZ or LM34DZ
See NS Package Number Z03A
TL/H/6685–20
Top View
e
N.C.
No Connection
Order Number LM34DM
See NS Package Number M08A
Typical Applications
TL/H/6685–3
FIGURE 1. Basic Fahrenheit Temperature Sensor
a
5 to 300 F)
a
(
§
§
TL/H/6685–4
FIGURE 2. Full-Range Fahrenheit Temperature Sensor
TRI-STATEÉ is a registered trademark of National Semiconductor Corporation.
C
1995 National Semiconductor Corporation
TL/H/6685
RRD-B30M75/Printed in U. S. A.