LM27-2HJ

V+=2.7V

to 5.5V

VTEMP

GND

HYST

OS

HYST

REF

TEMP

SENSOR

+

-

HYST=GND for 10

oC Hysteresis

HYST=V+ for 2

oC Hysteresis

VTEMP=(-3.552x10

-6x(T-30)2)+(-10.69576x10-3x(T-30))+1.8386V

TOS

TOS- THYST

Temp. of

Leads

OS

LM27

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SNIS124D – AUGUST 2002 – REVISED JULY 2013

LM27 SOT-23, ±3°C Accurate, 120°C-150°C Factory Preset Thermostat

Check for Samples: LM27

1

FEATURES

DESCRIPTION

The LM27 is a precision, single digital-output, low-

2

•

Internal Comparator with Pin Selectable 2°C or

power thermostat comprised of an internal reference,

10°C Hysteresis

DAC, temperature sensor and comparator. Utilizing

•

No External Components Required

factory programming, it can be manufactured with

•

Open-drain or Push-pull Digital Output;

different trip points as well as different digital output

functionality. The trip point (TOS) can be preset at the

Supports CMOS Logic Levels

factory to any temperature in the range of +120°C to

•

Internal Temperature Sensor with VTEMP Output

+150°C in 1°C increments. The LM27 has one digital

Pin

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

•

VTEMP Output Allows After-assembly System

one analog output (VTEMP). The digital output stage

Testing

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

addition, it can be factory programmed to be active

•

Internal Voltage Reference and DAC for Trip-

HIGH or LOW. The digital output can be factory

point Setting

programmed

to

indicate

an

over

temperature

•

Currently Available in 5-pin SOT-23 Plastic

shutdown event (OS or OS) or an under temperature

Package

shutdown event (US or US). When preset as an

•

Excellent Power Supply Noise Rejection

overtemperature shutdown (OS) it will go LOW to

indicate that the die temperature is over the internally

preset TOS and go HIGH when the temperature goes

APPLICATIONS

below (TOS–THYST). Similarly, when preprogrammed

•

Microprocessor Thermal Management

as an undertemperature shutdown (US) it will go

•

Appliances

HIGH to indicate that the temperature is below TUS

and go LOW when the temperature is above

•

Portable Battery Powered Systems

(TUS+THYST). The typical hysteresis, THYST, can be set

•

Fan Control

to 2°C or 10°C and is controlled by the state of the

•

Industrial Process Control

HYST pin. A VTEMP analog output provides a voltage

that is proportional to temperature and has a

•

HVAC Systems

−10.7mV/°C output slope.

•

Electronic System Protection

Currently, there are several standard parts available,

see Table 1. For other part options, contact a Texas

KEY SPECIFICATIONS

Instruments Distributor or Sales Representative for

•

Power Supply Voltage 2.7V to 5.5V

information on minimum order qualification. The

•

Power Supply Current 40

μA (Max), 15μA (Typ)

LM27 is currently available in a 5-lead SOT-23

package.

•

Hysteresis Temperature 2°C or 10°C (Typ)

•

Temperature Trip Point Accuracy ±3°C (Max)

Simplified Block Diagram and Connection Diagram LM27CIM5-2HJ (140°C Trip-Point)

1

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2

All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Copyright © 2002–2013, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.