LM45B LM45C
SOT-23 Precision Centigrade Temperature Sensors
May 1995
LM45B LM45C
SOT-23 Precision Centigrade Temperature Sensors
General Description
The LM45 series are precision integrated-circuit tempera-
ture sensors whose output voltage is linearly proportional to
the Celsius (Centigrade) temperature The LM45 does not
require any external calibration or trimming to provide accu-
racies of
g
2 C at room temperature and
g
3 C over a full
b
20 to
a
100 C temperature range Low cost is assured by
trimming and calibration at the wafer level The LM45’s low
output impedance linear output and precise inherent cali-
bration make interfacing to readout or control circuitry espe-
cially easy It can be used with a single power supply or with
plus and minus supplies As it draws only 120
mA
from its
supply it has very low self-heating less than 0 2 C in still
air The LM45 is rated to operate over a
b
20 to
a
100 C
temperature range
Y
Y
Y
Y
Y
Y
Portable Medical Instruments
HVAC
Power Supply Modules
Disk Drives
Computers
Automotive
Features
Y
Y
Y
Y
Y
Y
Y
Applications
Y
Y
Y
Y
Y
Y
Y
Battery Management
FAX Machines
Printers
Calibrated directly in Celsius (Centigrade)
Linear
a
10 0 mV C scale factor
g
3 C accuracy guaranteed
Rated for full
b
20 to
a
100 C range
Suitable for remote applications
Low cost due to wafer-level trimming
Operates from 4 0V to 10V
Less than 120
mA
current drain
Low self-heating 0 20 C in still air
Nonlinearity only
g
0 8 C max over temp
Low impedance output 20X for 1 mA load
Connection Diagram
SOT-23
Order
Number
LM45BIM3
LM45BIM3X
TL H 11754 – 1
SOT-23
Device
Marking
T4B
T4B
T4C
T4C
Supplied As
250 Units on Tape and Reel
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
Top View
See NS Package Number M03B
(JEDEC Registration TO-236AB)
LM45CIM3
LM45CIM3X
Typical Applications
TL H 11754 – 3
FIGURE 1 Basic Centigrade Temperature
Sensor (
a
2 5 C to
a
100 C)
Choose R
1
e b
V
S
50
mA
V
OUT
e
(10 mV C
c
Temp C)
V
OUT
e a
1 000 mV at
a
100 C
e a
250 mV at
a
25 C
e b
200 mV at
b
20 C
TL H 11754 – 4
FIGURE 2 Full-Range Centigrade
Temperature Sensor (
b
20 C to
a
100 C)
C
1995 National Semiconductor Corporation
TL H 11754
RRD-B30M75 Printed in U S A
NSC [ NATIONAL SEMICONDUCTOR ]
