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LM99  Product Folder

±1°C Accurate, Remote Diode and Local Digital Temperature Sensor with Two-Wire Interface
Generic P/N 99
General
Description		 Features Datasheet Package
& Models		 Samples
& Pricing

Datasheet

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LM99 ±1°C Accurate, High Temperature, Remote Diode Temperature Sensor with Two-Wire Interface 349 Kbytes 16-Jul-03 View Online Download Receive via Email

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Package Availability, Models, Samples & Pricing

Part NumberPackageStatusModelsSamples &
Electronic
Orders		Budgetary PricingStd
Pack
Size		Package
Marking
TypePinsMSL/Lead-Free AvailabilityLead
Time		QtySPICEIBISQty$US each
LM99-1EVALevaluation boardFull production N/AN/A   N/A-
6 weeks0
LM99EVALevaluation boardFull production N/AN/A   N/A-
6 weeks0
LM99-1CIMMMINI SOIC8StatusFull productionN/AN/ASamples1K+$1.99reel
of
1000		ZXTT
T20C
10-12 weeks0
LM99CIMMMINI SOIC8StatusFull productionN/AN/A24 Hour Samples
Buy Now 		1K+$1.99reel
of
1000		ZXTT
T17C
10-12 weeks0

General Description

The LM99 is an 11-bit remote diode temperature sensor with a 2-wire System Management Bus (SMBus) serial interface. The LM99 accurately measures: (1) its own temperature and (2) the temperature of a remote diode-connected transistor such as the 2N3904 or a thermal diode commonly found on Graphics Processor Units (GPU), Computer Processor Units (CPU or other ASICs. The LM99 remote diode temperature sensor shifts the temperature from the remote sensor down 16°C and operates on that shifted temperature:

The local temperature reading requires no offset.

The LM99 has an Offset Register which provides a means for precise matching to various thermal diodes. Contact hardware.monitor@nsc.com for the latest details.

The LM99 and LM99-1 have the same functions but different SMBus slave addresses. This allows for one of each to be on the same bus at the same time.

Activation of the ALERT# output occurs when any temperature goes outside a preprogrammed window set by the HIGH and LOW temperature limit registers or exceeds the T_CRIT temperature limit. Activation of the T_CRIT_A# occurs when any temperature exceeds the T_CRIT programmed limit.

Features

  • Accurately senses the temperature of remote diodes
  • Offset register allows use of a variety of thermal diodes
  • On-board local temperature sensing
  • 10 bit plus sign remote diode temperature data format, 0.125 °C resolution
  • T_CRIT_A# output useful for system shutdown
  • ALERT# output supports SMBus 2.0 protocol
  • SMBus 2.0 compatible interface, supports TIMEOUT
  • 8-pin MSOP package

Key Specification

Supply Voltage3.0 V to 3.6 V
Supply Current0.8 mA (typ)
Local Temp Accuracy (includes quantization error)
TA = 25°C to 125°C±3.0°C (max)
Remote Diode Temp Accuracy (includes quantization error)
TA= 30°C to 50°C, TD= 120°C to 140°C±1.0°C (max)
TA= 0°C to 85°C, TD= 25°C to 140°C±3.0°C (max)

Applications

  • Graphics Processor Thermal Management
  • Computer Processor Thermal Management
  • Electronic Test Equipment
  • Office Electronics
[Information as of 15-Jan-2004]

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