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

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

Datasheet	Packaging	Samples & Pricing	Eval. Boards	Reliability	Design Tools	Knowledge Base

Features

•	Accurately senses die temperature of remote ICs or diode junctions
•	Offset register allows sensing a variety of thermal diodes accurately
•	On-board local temperature sensing
•	10 bit plus sign remote diode temperature data format, 0.125 °C resolution
•	Diode fault detection circuitry
•	T_CRIT_A# output useful for system shutdown (open diode does not activate T_CRIT_A#)
•	ALERT# output supports SMBus 2.0 protocol
•	SMBus 2.0 compatible interface, supports TIMEOUT
•	8-pin MSOP packages

Key Specification

Supply Voltage	3.0V to 3.6V
Supply Current	0.8mA (typ)
Local Temp Accuracy (includes quantization error)
T_A=25°C to 125°C	±4.0°C (max)
Remote Diode Temp Accuracy (includes quantization error)
T_A=30°C to 50°C, T_D=60°C to 100°C	±3.0°C (max)
T_A=0°C to 85°C, T_D=25°C to 125°C	±4.0°C (max)

General Description

The LM90 is an 11-bit digital temperature sensor with a 2-wire System Management Bus (SMBus) serial interface. More...

Applications

•	System Thermal Management (e.g. Laptop, Desktop, Workstations, Server)
•	Electronic Test Equipment
•	Office Electronics

Typical Application

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Parametric Table expand

Parametric Table collapse

Remote Diode Thermal Sensors 1

Supply Min 3 Volt

Quiescent Current 1.7 mA

Temperature Min 0 deg C

Temperature Max 125 deg C

Interface Type 2-Wire Serial

Remote Diode Thermal Sensors 1

Temperature Accuracy (+/-) 3 deg C

Supply Min 3 Volt

Quiescent Current 1.7 mA

Temperature Min 0 deg C

Temperature Max 125 deg C

Interface Type 2-Wire Serial

Programmable Setpoints Yes

Resolution 11 bit

Resolution degC/LSB 0.125

Supply Max 3.6 Volt

Shut down Yes

Interrupt Outputs 2

Fault Queue Yes

View Using Catalog

Typical Performance

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Additional Resources

Design Tools (see below)

Block Diagram

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Datasheet

RoHS Compliance Information	Size in Kbytes	Date
LM90 ±3°C Accurate, Remote Diode and Local Digital Temperature Sensor with Two-Wire Interface	384 Kbytes	19-Feb-02	View Online Download
LM90 ±3°C Accurate, Remote Diode and Local Digital Temperature Sensor with Two-Wire Interface (Japanese)	273 Kbytes

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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

LM90EVAL

LM90EVAL Evaluation Board

Full production

N/A

$78.00

8 weeks

N/A

LM90CIMM

MINI SOIC

STD

NOPB

260

RoHS

Download

Full production

N/A

1K+

$0.72

reel
of
1000

ZXTT
T11C

6 weeks

2000

General Description

The LM90 is an 11-bit digital temperature sensor with a 2-wire System Management Bus (SMBus) serial interface. The LM90 accurately measures its own temperature as well as the temperature of an external device, such as processor thermal diode or diode connected transistor such as the 2N3904. The temperature of any ASIC can be accurately determined using the LM90 as long as a dedicated diode (semiconductor junction) is available on the target die. The LM90 remote sensor accuracy of ±3°C is factory trimmed for the 1.008 typical non-ideality factor of the mobile Pentium™ III thermal diode. The LM90 has an Offset register to allow measuring other diodes without requiring continuous software management. Contact hardware.monitor.team@nsc.com to obtain the latest data for new processors.

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. The LM90 is pin and register compatible with the LM86, Analog Devices ADM1032 and Maxim MAX6657/8.

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM *	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM90CIMM	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.

Design Tools

Title	Size in Kbytes	Date
SensorEval Software for Thermal Mangement Products	6 Kbytes	15-May-2008	View

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[Information as of 7-Jan-2009]