LM26

General Description

The LM26 is a precision, single digital-output, low-power

thermostat comprised of an internal reference, DAC, tem-

perature sensor and comparator. Utilizing factory program-

ming, it can be manufactured with different trip points as well

as different digital output functionality. The trip point (T

can be preset at the factory to any temperature in the range

of −55˚C to +110˚C in 1˚C increments. The LM26 has one

digital output (OS/OS/US/US), one digital input (HYST) and

one analog output (V

preset as either open-drain or push-pull. In addition, it can be

factory programmed to be active HIGH or LOW. The digital

output can be factory programmed to indicate an over tem-

perature shutdown event (OS or OS) or an under tempera-

ture shutdown event (US or US). When preset as an over-

temperature shutdown (OS) it will go LOW to indicate that

the die temperature is over the internally preset T

HIGH when the temperature goes below (T

larly, when preprogrammed as an undertemperature shut-

down (US) it will go HIGH to indicate that the temperature is

below T

(T

2˚C or 10˚C and is controlled by the state of the HYST pin. A

V

to temperature and has a −10.82mV/˚C output slope.

Available parts are detailed in the ordering information. For

other part options, contact a National Semiconductor Dis-

tributor or Sales Representative for information on minimum

order qualification. The LM26 is currently available in a

5-lead SOT-23 package.

Applications

n

Microprocessor Thermal Management

n

Appliances

n

Portable Battery Powered Systems

n

Fan Control

n

Industrial Process Control

n

HVAC Systems

n

Remote Temperature Sensing

n

Electronic System Protection

Features

n

Internal comparator with pin programmable 2˚C or 10˚C

hysteresis

n

No external components required

n

Open Drain or push-pull digital output; supports CMOS

logic levels

n

Internal temperature sensor with V

n

V

n

Internal voltage reference and DAC for trip-point setting

n

Currently available in 5-pin SOT-23 plastic package

n

Excellent power supply noise rejection

Key Specifications

2.7V to 5.5V

40µA(max)

20µA(typ)

2˚C or 10˚C(typ)

Temperature Trip Point Accuracy

Temperature Range

LM26CIM

−55˚C to +110˚C

+120˚C

LM26CIM5-TPA Simplified Block Diagram and Connection Diagram

10132301

The LM26CIM5-TPA has a fixed trip point of 85˚C.

For other trip point and output function availability,

please see ordering information or contact National Semiconductor.

March 2005

© 2005 National Semiconductor Corporation

DS101323

www.national.com