LM56 Dual Output Low Power Thermostat
April 2000
LM56
Dual Output Low Power Thermostat
General Description
The LM56 is a precision low power thermostat. Two stable
temperature trip points (V
T1
and V
T2
) are generated by divid-
ing down the LM56 1.250V bandgap voltage reference using
3 external resistors. The LM56 has two digital outputs. OUT1
goes LOW when the temperature exceeds T1 and goes
HIGH when the the temperature goes below (T1–T
HYST
).
Similarly, OUT2 goes LOW when the temperature exceeds
T2 and goes HIGH when the temperature goes below
(T2–T
HYST
). T
HYST
is an internally set 5˚C typical hysteresis.
The LM56 is available in an 8-lead Mini-SO8 surface mount
package and an 8-lead small outline package.
Features
n
n
n
n
n
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Digital outputs support TTL logic levels
Internal temperature sensor
2 internal comparators with hysteresis
Internal voltage reference
Currently available in 8-pin SO plastic package
Future availability in the 8-pin Mini-SO8 package
Key Specifications
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Power Supply Voltage
n
Power Supply Current
n
V
REF
n
Hysteresis Temperature
n
Internal Temperature Sensor
Output Voltage
(+6.20 mV/˚C x T) +395 mV
n
Temperature Trip Point Accuracy:
LM56BIM
+25˚C
+25˚C to +85˚C
−40˚C to +125˚C
LM56CIM
2.7V–10V
230 µA (max)
1.250V
±
1% (max)
5˚C
Applications
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n
n
n
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Microprocessor Thermal Management
Appliances
Portable Battery Powered 3.0V or 5V Systems
Fan Control
Industrial Process Control
HVAC Systems
Remote Temperature Sensing
Electronic System Protection
±
2˚C (max)
±
2˚C (max)
±
3˚C (max)
±
3˚C (max)
±
3˚C (max)
±
4˚C (max)
Simplified Block Diagram and Connection Diagram
DS012893-2
DS012893-1
Order
Number
NS
Package
Number
Transport
Media
Package
Marking
LM56BIM LM56BIMX
M08A
SOP-8
M08A
SOP-8
2500 Units
Rail
LM56BIM
Tape &
Reel
LM56BIM
LM56CIM LM56CIMX
M08A
SOP-8
M08A
SOP-8
2500 Units
Rail
LM56CIM
Tape &
Reel
LM56CIM
LM56BIMM
MUA08A
MSOP-8
LM56BIMMX
MUA08A
MSOP-8
3500 Units
LM56CIMM
MUA08A
MSOP-8
LM56CIMMX
MUA08A
MSOP-8
3500 Units
Rail
T02B
Tape & Reel
T02B
Rail
T02C
Tape & Reel
T02C
© 2000 National Semiconductor Corporation
DS012893
www.national.com
NSC [ NATIONAL SEMICONDUCTOR ]
