Features • Accurately senses die temperature of 4 remote ICs or diode junctions and local temperature • TruTherm BJT beta compensation technology accurately senses sub-micron process thermal diodes • Programmable digital filters and analog front end filter • 0.125°C LSb temperature resolution • 0.03125°C LSb remote temperature resolution with digital filter enabled • +127.875°C/–128°C and 0°C/255°C remote ranges • Remote diode fault detection, model selection and offset correction • Mask and status register support • 3 programmable ^TCRIT outputs with programmable shared hysteresis and Fault-Queue • Programmable conversion rate and shutdown mode one-shot conversion control • SMBus 2.0 compatible interface, supports TIMEOUT • Three-level address pin • 14-pin LLP package Description LM95234 is an 11-bit digital temperature sensor with a 2-wire System Management Bus (SMBus) interface that can very accurately monitor the temperature of four remote diodes as well as its own temperature that includes patent pending remote diode TruTherm BJT beta compensation beta compensation technology. The four remote diodes can be external devices such as microprocessors, graphics processors or diode-connected 2N3904s. The LM95234's TruTherm BJT beta compensation technology allows sensing of 90 nm or 65 nm process thermal diodes accurately. The LM95234 reports temperature in two different formats for +127.875°C/–128°C range and 0°C/255°C range. The LM95234 ^TCRIT1, ^TCRIT2 and ^TCRIT3 outputs are triggered when any unmasked channel exceeds its corresponding programmable limit and can be used to shutdown the system, to turn on the system fans or as a microcontroller interrupt function. The current status of the ^TCRIT1, ^TCRIT2 and ^TCRIT3 pins can be read back from the status registers. Mask registers are available for further control of the ^TCRIT outputs. Two LM95234 remote temperature channels have programmable digital filters while the other two remote channels utilize a fault-queue to minimize unwanted ^TCRIT events when temperature spikes are encountered. For optimum flexibility and accuracy, each LM95234 channel includes registers for sub-micron process or 2N3904 diode model selection as well as offset correction. A three-level address pin allows connection of up to 3 LM95234s to the same SMBus master. The LM95234 includes power saving functions such as: programmable conversion rate, shutdown mode, and disabling of unused channels. Key Specification ■  Local Temperature Accuracy ±2.0°C (max) ■  Remote Diode Temperature Accuracy ±0.875°C (max) ■  Supply Voltage 3.0V to 3.6V ■  Average Supply Current    (1Hz conversion rate) 0.57 mA (typ) Applications • Processor/Computer System Thermal Management   (e.g. Laptop, Desktop, Workstations, Server) • Electronic Test Equipment • Office Electronics

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Typical Application click for larger image
Typical Performance *click for larger image Thermal Diode Performance Comparison

Datasheet

Title		Size	Date	Other Language
	LM95234 Quad Remote Diode and Local Temperature Sensor with SMBus Interface and TruTherm™ Technology	849 Kbytes	27-Jun-07

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Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM95234CISD	CMOS7	0	18406	0	0	1089000	4	309006723
LM95234CISDX	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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