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 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. Key Specification Remote Temperature Accuracy ±0.75°C (max) Local Temperature Accuracy ±3.0°C (max) Supply Voltage 3.0V to 3.6V Supply Current 402µA (typ) Applications • Processor/Computer System Thermal Management (e.g. Laptop, Desktop, Workstations, Server) • Electronic Test Equipment • Office Electronics

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Datasheet

Title		Size	Date	Other Language
	LM95231 Precision Dual Remote Diode Temperature Sensor with SMBus Interface and TruTherm™ Technology	709 Kbytes	10-Aug-06

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Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM95231BIMM-1	CMOS7	0	18406	0	0	1089000	4	309006723
LM95231BIMM-2	CMOS7	0	18406	0	0	1089000	4	309006723
LM95231BIMMX	CMOS7	0	18406	0	0	1089000	4	309006723
LM95231BIMMX-1	CMOS7	0	18406	0	0	1089000	4	309006723
LM95231BIMMX-2	CMOS7	0	18406	0	0	1089000	4	309006723
LM95231CIMM	CMOS7	0	18406	0	0	1089000	4	309006723
LM95231CIMM-1	CMOS7	0	18406	0	0	1089000	4	309006723
LM95231CIMM-2	CMOS7	0	18406	0	0	1089000	4	309006723
LM95231CIMMX	CMOS7	0	18406	0	0	1089000	4	309006723
LM95231CIMMX-1	CMOS7	0	18406	0	0	1089000	4	309006723
LM95231CIMMX-2	CMOS7	0	18406	0	0	1089000	4	309006723

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.

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