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

	LM27 - SOT-23, ±3°C Accurate, 120°C-150°C Factory Preset Thermostat from the PowerWise® Family

Datasheet	Packaging	Samples & Pricing	Reliability	Application Notes	Knowledge Base

Features

•	Internal comparator with pin selectable 2°C or 10°C hysteresis
•	No external components required
•	Open-drain or push-pull digital output; supports CMOS logic levels
•	Internal temperature sensor with V_TEMP output pin
•	V_TEMP output allows after-assembly system testing
•	Internal voltage reference and DAC for trip-point setting
•	Currently available in 5-pin SOT-23 plastic package
•	Excellent power supply noise rejection

Key Specification

Power Supply Voltage	2.7V to 5.5V
Power Supply Current	40µA(max) 15µA(typ)
Hysteresis Temperature	2°C or 10°C(typ)
Temperature Trip Point Accuracy	±3°C (max)

General Description

The LM27 is a precision, single digital-output, low-power thermostat comprised of an internal reference, DAC, temperature sensor and comparator. More...

Applications

•	Microprocessor Thermal Management
•	Appliances
•	Portable Battery Powered Systems
•	Fan Control
•	Industrial Process Control
•	HVAC Systems
•	Electronic System Protection

Typical Application

click for larger image

Parametric Table expand

Parametric Table collapse

SetPoint Type Fixed

SetPoint Value 130, 120, 140 deg C

Temperature Accuracy (+/-) 3 deg C

Supply Min 2.7 Volt

Temperature Min 120 deg C

Temperature Max 150 deg C

Quiescent Current_ 40 uA

SetPoint Type Fixed

SetPoint Value 130, 120, 140 deg C

Temperature Accuracy (+/-) 3 deg C

Supply Min 2.7 Volt

Temperature Min 120 deg C

Temperature Max 150 deg C

Quiescent Current_ 40 uA

Comparators 1

Sensor Gain -10.82 mV/Deg C

Remote Diode Thermal Sensors Undefined

Supply Max 5.5 Volt

VtempOutput Impedance 18 Ohm

Reference Output Undefined Volt

Quiescent Current 0.04 mA

Automotive Selection Guide Yes

PowerWise Yes

View Using Catalog

Additional Resources

Application Notes (see below)

Block Diagram

click for larger image

Datasheet

RoHS Compliance Information	Size in Kbytes	Date
LM27 SOT-23, ±3°C Accurate, 120°C-150°C Factory Preset Thermostat	586 Kbytes	5-Oct-06	View Online Download
LM27 SOT-23, ±3°C Accurate, 120°C-150°C Factory Preset Thermostat (Japanese)	348 Kbytes

If you have trouble printing or viewing PDF file(s), see Printing Problems.

Package Availability, Models, Samples & Pricing

Part Number

Package

Factory Lead Time

Models

Samples &
Electronic
Orders

Budgetary Pricing

Std
Pack
Size

Package
Marking
Format

Type

Pins

Spec.

MSL
Rating

Peak
Reflow

RoHS
Report

CAD
Symbols

Weeks

Qty

$US each

LM27CIM5-1HJ

SOT-23

STD

NOPB

260

RoHS

Download

Full production

N/A

1K+

$0.79

reel
of
1000

T1HJ
XTT

8 weeks

2000

LM27CIM5-2HJ

SOT-23

NOPB

260

RoHS

Download

Full production

N/A

1K+

$0.79

reel
of
1000

T2HJ
XTT

12 weeks

2000

LM27CIM5-ZHJ

SOT-23

NOPB

260

RoHS

Download

Full production

N/A

1K+

$0.79

reel
of
1000

TZHJ
XTT

6 weeks

LM27-2PL MDA

Unpackaged Die

Full production

N/A

CALL

tray
of
N/A

N/A

40000

General Description

The LM27 is a precision, single digital-output, low-power thermostat comprised of an internal reference, DAC, temperature sensor and comparator. Utilizing factory programming, it can be manufactured with different trip points as well as different digital output functionality. The trip point (T_OS) can be preset at the factory to any temperature in the range of +120°C to +150°C in 1°C increments. The LM27 has one digital output (OS/OS#/US/US#), one digital input (HYST) and one analog output (V_TEMP). The digital output stage can be 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 temperature shutdown event (OS or OS#) or an under temperature shutdown event (US or US#). When preset as an overtemperature shutdown (OS#) it will go LOW to indicate that the die temperature is over the internally preset T_OS and go HIGH when the temperature goes below (T_OS-T_HYST). Similarly, when preprogrammed as an undertemperature shutdown (US) it will go HIGH to indicate that the temperature is below T_US and go LOW when the temperature is above (T_US+T_HYST). The typical hysteresis, T_HYST, can be set to 2°C or 10°C and is controlled by the state of the HYST pin. A V_TEMP analog output provides a voltage that is proportional to temperature and has a -10.7mV/°C output slope.

Currently, there are several standard parts available, see ordering information for details. For other part options, contact a National Semiconductor Distributor or Sales Representative for information on minimum order qualification. The LM27 is currently available in a 5-lead SOT-23 package.

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM *	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM27-2PL MDA	CMOS7	0	13906	0	0	862500	5	244736730
LM27CIM5-1HJ	CMOS7	0	13906	0	0	862500	5	244736730
LM27CIM5-2HJ	CMOS7	0	13906	0	0	862500	5	244736730
LM27CIM5-ZHJ	CMOS7	0	13906	0	0	862500	5	244736730

Note: The Early Failure Rates were calculated as point estimates. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

For more information on Reliability Metrics, please click here.

More Application Notes

Title	Size in Kbytes	Date
AN-1256: Application Note 1256 Tiny Temperature Sensors for Portable Systems	66 Kbytes	1-Oct-02	Download

If you have trouble printing or viewing PDF file(s), see Printing Problems.

[Information as of 7-Jan-2009]