April 2000
LM66
Dual Output Internally Preset Thermostat
n Electronic System Protection
General Description
The LM66 is a precision low power thermostat. Two stable
Features
n Digital outputs support TTL logic levels
n Internal temperature sensor
n 2 internal comparators with hysteresis
n Internal voltage reference
n Currently available in 8-pin SO plastic package
temperature trip points (VT1 and VT2) are generated by divid-
ing down the LM66 1.250V bandgap voltage reference using
a resistors divider network. The LM66 has two digital out-
puts. OUT1 goes LOW when the temperature exceeds T1
and goes HIGH when the the temperature goes below
(T1–THYST). Similarly, OUT2 goes LOW when the tempera-
ture exceeds T2 and goes HIGH when the temperature goes
below (T2–THYST). THYST is an internally set 5˚C typical hys-
teresis.
Key Specifications
The LM66 is currently available in an 8-lead small outline
package.
j
j
j
j
j
Power Supply Voltage
Power Supply Current
VREF
2.7V to 10V
250 µA (max)
±
1.250V 1.4% (max)
Applications
n Microprocessor Thermal Management
n Appliances
Hysteresis Temperature
Internal Temperature Sensor
5˚C
Output Voltage
n Temperature Trip Point Accuracy
n T1 set point
(+6.20 mV/˚C x T) +400 mV
n Portable Battery Powered 3.0V or 5V Systems
n Fan Control
n Industrial Process Control
n HVAC Systems
±
3˚C (max)
+73˚C
n T2 set point
+82˚C
n Remote Temperature Sensing
Simplified Block Diagram and
Connection Diagram
Ordering Information
TABLE 1.
Order Number
LM66CIM-
RLSKB
LM66CIMX-
RLSKB
NS Tackage
Number
M08A
M08A
Transport Media
Bulk Rail
2500 Units Tape
& Reel
DS100854-1
Typical Application
DS100854-2
DS100854-3
© 2000 National Semiconductor Corporation
DS100854
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