LM45 SOT-23 Precision Centigrade Temperature Sensors
July 1999
LM45
SOT-23 Precision Centigrade Temperature Sensors
General Description
The LM45 series are precision integrated-circuit temperature
sensors, whose output voltage is linearly proportional to the
Celsius (Centigrade) temperature. The LM45 does not re-
quire any external calibration or trimming to provide accura-
cies of
鹵
2藲C at room temperature and
鹵
3藲C over a full 鈭?0 to
+100藲C temperature range. Low cost is assured by trimming
and calibration at the wafer level. The LM45鈥檚 low output im-
pedance, linear output, and precise inherent calibration
make interfacing to readout or control circuitry especially
easy. It can be used with a single power supply, or with plus
and minus supplies. As it draws only 120 碌A from its supply,
it has very low self-heating, less than 0.2藲C in still air. The
LM45 is rated to operate over a 鈭?0藲 to +100藲C temperature
range.
n
n
n
n
n
n
Portable Medical Instruments
HVAC
Power Supply Modules
Disk Drives
Computers
Automotive
Features
n
n
n
n
n
n
n
n
n
n
n
Calibrated directly in 藲 Celsius (Centigrade)
Linear + 10.0 mV/藲C scale factor
鹵
3藲C accuracy guaranteed
Rated for full 鈭?0藲 to +100藲C range
Suitable for remote applications
Low cost due to wafer-level trimming
Operates from 4.0V to 10V
Less than 120 碌A current drain
Low self-heating, 0.20藲C in still air
Nonlinearity only
鹵
0.8藲C max over temp
Low impedance output, 20鈩?for 1 mA load
Applications
n
Battery Management
n
FAX Machines
n
Printers
Connection Diagram
SOT-23
Order
Number
LM45BIM3
LM45BIM3X
LM45CIM3
LM45CIM3X
DS011754-1
SOT-23
Device
Marking
T4B
T4B
T4C
T4C
Supplied As
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
Top View
See NS Package Number MA03B
Typical Applications
DS011754-3
FIGURE 1. Basic Centigrade Temperature
Sensor (+2.5藲C to +100藲C)
DS011754-4
Choose R
1
= 鈭扸
S
/50 碌A
V
OUT
= (10 mV/藲C x Temp 藲C)
V
OUT
= +1,000 mV at +100藲C
= +250 mV at +25藲C
= 鈭?00 mV at 鈭?0藲C
FIGURE 2. Full-Range Centigrade
Temperature Sensor (鈭?0藲C to +100藲C)
漏 1999 National Semiconductor Corporation
DS011754
www.national.com
1
2
3
4
5
6
7
8
9
