LM56 Dual Output Low Power Thermostat
August 22, 2009
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
■
■
■
■
■
Digital outputs support TTL logic levels
Internal temperature sensor
2 internal comparators with hysteresis
Internal voltage reference
Available in 8-pin SO and Mini-SO8 plastic packages
Key Specifications
■
Power Supply Voltage
■
Power Supply Current
■
V
REF
■
Hysteresis Temperature
■
Internal Temperature Sensor Output Voltage:
(+6.20 mV/°C x T) + 395 mV
2.7V–10V
230 μA
(max)
1.250V ±1% (max)
5°C
Applications
■
■
■
■
■
■
■
■
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
■
Temperature Trip Point Accuracy:
LM56BIM
+25°C
+25°C to +85°C
−40°C to +125°C
±2°C (max)
±2°C (max)
±3°C (max)
LM56CIM
±3°C (max)
±3°C (max)
±4°C (max)
Simplified Block Diagram and Connection Diagram
1289302
1289301
Order
Number
NS Package
Number
Transport
Media
Package
Marking
LM56BIM LM56BIMX LM56CIM LM56CIMX LM56BIMM LM56BIMMX LM56CIMM LM56CIMMX
M08A
SOP-8
Rail
LM56BIM
M08A
SOP-8
2500 Units
Tape & Reel
LM56BIM
M08A
SOP-8
Rail
LM56CIM
M08A
SOP-8
MUA08A
MSOP-8
MUA08A
MSOP-8
MUA08A
MSOP-8
MUA08A
MSOP-8
2500 Units 1000 Units
3500 Units
1000 Units
3500 Units
Tape & Reel Tape & Reel Tape & Reel Tape & Reel Tape & Reel
LM56CIM
T02B
T02B
T02C
T02C
© 2009 National Semiconductor Corporation
12893
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