LM99

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SNIS129D – JANUARY 2003 – REVISED MARCH 2013

LM99 ±1°C Accurate, High Temperature, Remote Diode Temperature Sensor with Two-

Wire Interface

Check for Samples: LM99

1

FEATURES

DESCRIPTION

The LM99 is an 11-bit remote diode temperature

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•

Accurately Senses the Temperature of Remote

sensor with a 2-wire System Management Bus

Diodes

(SMBus)

serial

interface.

The

LM99

accurately

•

Offset Register Allows Use of a Variety of

measures: (1) its own temperature and (2) the

Thermal Diodes

temperature of a remote diode-connected transistor

such as the 2N3904 or a thermal diode commonly

•

On-board Local Temperature Sensing

found on Graphics Processor Units (GPU), Computer

•

10 Bit Plus Sign Remote Diode Temperature

Processor Units (CPU or other ASICs. The LM99

Data Format, 0.125 °C Resolution

remote

diode

temperature

sensor

shifts

the

•

T_CRIT_A Output Useful for System Shutdown

temperature from the remote sensor down 16°C and

operates on that shifted temperature:

•

ALERT Output Supports SMBus 2.0 Protocol

•

SMBus 2.0 Compatible Interface, Supports

TIMEOUT

The local temperature reading requires no offset.

•

8-Pin VSSOP Package

The LM99 has an Offset Register which provides a

means for precise matching to various thermal

APPLICATIONS

diodes.

•

Graphics Processor Thermal Management

The LM99 and LM99-1 have the same functions but

•

Computer Processor Thermal Management

different SMBus slave addresses. This allows for one

•

Electronic Test Equipment

of each to be on the same bus at the same time.

•

Office Electronics

Activation of the ALERT output occurs when any

temperature goes outside a preprogrammed window

KEY SPECIFICATIONS

set by the HIGH and LOW temperature limit registers

or exceeds the T_CRIT temperature limit. Activation

•

Supply Voltage 3.0 V to 3.6 V

of the T_CRIT_A occurs when any temperature

•

Supply Current 0.8 mA (typ)

exceeds the T_CRIT programmed limit.

•

Local Temp Accuracy

(Includes Quantization error)

–

•

Remote Diode Temp Accuracy

(Includes Quantization Error)

–

±1.0°C (Max)

–

(Max)

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

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PRODUCTION DATA information is current as of publication date.

Copyright © 2003–2013, 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.