LM56 Dual Output Low Power Thermostat
January 2006
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
dividing 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 tempera-
ture 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
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
j
Power Supply Voltage
j
Power Supply Current
j
V
REF
j
Hysteresis Temperature
2.7V–10V
230 µA (max)
1.250V
±
1% (max)
5˚C
Applications
n
n
n
n
n
n
n
n
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
j
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˚C (max)
±
2˚C (max)
±
3˚C (max)
±
3˚C (max)
±
3˚C (max)
±
4˚C (max)
Simplified Block Diagram and Connection Diagram
01289302
01289301
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
Rail
LM56CIM
M08A
SOP-8
M08A
SOP-8
2500 Units
Tape &
Reel
LM56CIM
MUA08A
MSOP-8
1000 Units
MUA08A
MSOP-8
3500 Units
MUA08A
MSOP-8
1000 Units
MUA08A
MSOP-8
3500 Units
Tape & Reel Tape & Reel Tape & Reel Tape & Reel
T02B
T02B
T02C
T02C
© 2006 National Semiconductor Corporation
DS012893
www.national.com
NSC [ NATIONAL SEMICONDUCTOR ]
