LM90

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SNIS126A – MAY 2004 – REVISED MARCH 2013

LM90 ±3°C Accurate, Remote Diode and Local Digital Temperature Sensor with Two-Wire

Interface

Check for Samples: LM90

1

FEATURES

DESCRIPTION

The LM90 is an 11-bit digital temperature sensor with

•

Accurately Senses Die Temperature of Remote

a 2-wire System Management Bus (SMBus) serial

ICs or Diode Junctions

interface. The LM90 accurately measures its own

•

Offset Register Allows Sensing a Variety of

temperature as well as the temperature of an external

Thermal Diodes Accurately

device, such as processor thermal diode or diode

connected transistor such as the 2N3904. The

•

On-board Local Temperature Sensing

temperature

of

any

ASIC

can

be

accurately

•

10 Bit Plus Sign Remote Diode Temperature

determined using the LM90 as long as a dedicated

Data Format, 0.125°C Resolution

diode (semiconductor junction) is available on the

•

Diode Fault Detection Circuitry

target die. The LM90 remote sensor accuracy of ±3°C

is factory trimmed for the 1.008 typical non-ideality

•

T_CRIT_A Output Useful for System Shutdown

factor of the mobile Pentium III thermal diode. The

(Open Diode does not Activate T_CRIT_A)

LM90 has an Offset register to allow measuring other

•

ALERT Output Supports SMBus 2.0 Protocol

diodes

without

requiring

continuous

software

•

SMBus 2.0 Compatible Interface, Supports

management.

TIMEOUT

Activation of the ALERT output occurs when any

•

8-pin VSSOP Package

temperature goes outside a preprogrammed window

set by the HIGH and LOW temperature limit registers

APPLICATIONS

or exceeds the T_CRIT temperature limit. Activation

of the T_CRIT_A occurs when any temperature

•

System Thermal Management

exceeds the T_CRIT programmed limit. The LM90 is

(e.g. Laptop, Desktop, Workstations, Server)

pin and register compatible with the LM86, Analog

•

Electronic Test Equipment

Devices ADM1032 and Maxim MAX6657/8.

•

Office Electronics

KEY SPECIFICATIONS

•

Supply Voltage 3.0 to 3.6 V

•

Supply Current 0.8 mA (Typ)

•

Local Temp Accuracy (Includes Quantization

Error)

–

•

Remote Diode Temp Accuracy (Includes

Quantization Error)

–

(Max)

–

(Max)

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.

PRODUCTION DATA information is current as of publication date.

Copyright © 2004–2013, 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.