LM95231 - Precision Dual Remote Diode Temperature Sensor with SMBus Interface and TruTherm™ Technology
Datasheet Packaging Samples & Pricing Eval. Boards Reliability Knowledge Base

Features
•Accurately senses die temperature of remote ICs or diode junctions
•Uses TruTherm technology for precision "thermal diode" temperature measurement
•Thermal diode input stage with analog filtering
•Thermal diode digital filtering
•Intel Pentium 4 processor on 90nm process or 2N3904 non-ideality selection
•Remote diode fault detection
•On-board local temperature sensing
•Remote temperature readings without digital filtering:
•0.125 °C LSb
•10-bits plus sign or 11-bits programmable resolution
•11-bits resolves temperatures above 127 °C
•Remote temperature readings with digital filtering:
•0.03125 °C LSb with filtering
•12-bits plus sign or 13-bits programmable resolution
•13-bits resolves temperatures above 127 °C
•Local temperature readings:
•0.25 °C
•9-bits plus sign
•Status register support
•Programmable conversion rate allows user optimization of power consumption
•Shutdown mode one-shot conversion control
•SMBus 2.0 compatible interface, supports TIMEOUT
•8-pin MSOP package

Key Specification

Remote Temperature Accuracy±0.75°C (max)
Local Temperature Accuracy±3.0°C (max)
Supply Voltage3.0V to 3.6V
Supply Current402µA (typ)

General Description

The LM95231 is a precision dual remote diode temperature sensor (RDTS) that uses National's TruTherm technology. More...


Applications

•Processor/Computer System Thermal Management (e.g. Laptop, Desktop, Workstations, Server)
•Electronic Test Equipment
•Office Electronics
  Typical Application
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ParametersValues
Remote Diode Thermal Sensors 2
Temperature Accuracy (+/-) 1.25 deg C
Supply Min 3 Volt
Quiescent Current 0.363 mA
Temperature Min 25 deg C
Temperature Max 140 deg C
Interface Type 2-Wire Serial
Programmable Setpoints No
TruTherm(TM) Beta Compensation Yes
Resolution 13 bits
Resolution degC/LSB 0.03125
Supply Max 3.6 Volt
Shut down Yes
Fault Queue No


Typical Performance

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  Block Diagram
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Datasheet
RoHS Compliance Information Size in KbytesDate Click link below to Download
LM95231 Precision Dual Remote Diode Temperature Sensor with SMBus Interface and TruTherm™ Technology 709
Kbytes		 10-Aug-06 Download

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


Package Availability, Models, Samples & Pricing
Part NumberPackageFactory Lead TimeModelsSamples &
Electronic
Orders		Budgetary PricingStd
Pack
Size		Package
Marking
Format
TypePinsSpec.MSL
Rating		Peak
Reflow		RoHS
Report		CAD
Symbols		WeeksQtyQty$US each
LM95231EVALLM95231EVAL Evaluation BoardFull productionN/A
 
Buy Now 		1+$120.001-
8 weeksN/A
LM95231CIMMMINI SOIC8NOPB1260RoHS Download Full productionN/A
Samples
Buy Now 		1K+$1.00reel
of
1000		ZXTT
T23C
6 weeksN/A
LM95231BIMM-1MINI SOIC8NOPB1260RoHS Download Full productionN/A
 
Buy Now 		1K+$1.17reel
of
1000		ZXTT
T25B
6 weeks2000
LM95231BIMM-2MINI SOIC8NOPB1260RoHS Download Full productionN/A
 
Buy Now 		1K+$1.17reel
of
1000		ZXTT
T26B
6 weeks1000
LM95231CIMM-1MINI SOIC8NOPB1260RoHS Download Full productionN/A
Samples
Buy Now 		1K+$1.00reel
of
1000		ZXTT
T25C
6 weeks1000
LM95231CIMM-2MINI SOIC8NOPB1260RoHS Download Full productionN/A
Samples
Buy Now 		1K+$1.00reel
of
1000		ZXTT
T26C
6 weeks3000
LM95231BIMMXMINI SOIC8NOPB1260RoHS Download Full productionN/A
 
Buy Now 		1K+$1.17reel
of
3500		ZXTT
T23B
16 weeksN/A
LM95231BIMMX-1MINI SOIC8NOPB1260RoHS Download Full productionN/A
 
Buy Now 		1K+$1.17reel
of
3500		ZXTT
T25B
16 weeksN/A
LM95231BIMMX-2MINI SOIC8NOPB1260RoHS Download Full productionN/A
 
Buy Now 		1K+$1.17reel
of
3500		ZXTT
T26B
16 weeksN/A
LM95231CIMMXMINI SOIC8NOPB1260RoHS Download Full productionN/A
 
Buy Now 		1K+$1.00reel
of
3500		ZXTT
T23C
16 weeksN/A
LM95231CIMMX-1MINI SOIC8NOPB1260RoHS Download Full productionN/A
 
Buy Now 		1K+$1.00reel
of
3500		ZXTT
T25C
16 weeksN/A
LM95231CIMMX-2MINI SOIC8NOPB1260RoHS Download Full productionN/A
 
Buy Now 		1K+$1.00reel
of
3500		ZXTT
T26C
6 weeksN/A

General Description

The LM95231 is a precision dual remote diode temperature sensor (RDTS) that uses National's TruTherm technology. The 2-wire serial interface of the LM95231 is compatible with SMBus 2.0. The LM95231 can sense three temperature zones, it can measure the temperature of its own die as well as two diode connected transistors. The LM95231 includes digital filtering and an advanced input stage that includes analog filtering and TruTherm technology that reduces processor-to-processor non-ideality spread. The diode connected transistors can be a "thermal diode" as found in Intel and AMD processors or can simply be a diode connected MMBT3904 transistor. TruTherm technology allows accurate measurement of "thermal diodes" found on small geometry processes, 90nm and below. The LM95231 supports user selectable thermal diode non-ideality of either a Pentium® 4 processor on 90nm process or 2N3904.

The LM95231 resolution format for remote temperature readings can be programmed to be 11-bits signed or unsigned with the digital filtering disabled. When the filtering is enabled the resolution increases to 13-bits signed or unsigned. In the unsigned mode the LM95231 remote diode readings can resolve temperatures above 127°C. Local temperature readings have a resolution of 9-bits plus sign.

Reliability Metrics

Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
LM95231BIMM-1CMOS70184060010890004309006723
LM95231BIMM-2CMOS70184060010890004309006723
LM95231BIMMXCMOS70184060010890004309006723
LM95231BIMMX-1CMOS70184060010890004309006723
LM95231BIMMX-2CMOS70184060010890004309006723
LM95231CIMMCMOS70184060010890004309006723
LM95231CIMM-1CMOS70184060010890004309006723
LM95231CIMM-2CMOS70184060010890004309006723
LM95231CIMMXCMOS70184060010890004309006723
LM95231CIMMX-1CMOS70184060010890004309006723
LM95231CIMMX-2CMOS70184060010890004309006723

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. 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.


[Information as of 8-Nov-2009]