LM40 - Hardware Monitor with Dual Thermal Diodes and SensorPath™ Bus [Life-time buy]

Datasheet Packaging Samples & Pricing Reliability Knowledge Base

Features
• SensorPath Interface
•2 hardware programmable addresses
•Voltage Monitoring
•9-bit [Sigma][Delta] ADC
•Internal scaling resistors for all inputs
•Monitors +1.2V, +2.5 V, +3.3 V, +5 V and +12 V
•Temperature Sensing
•2 remote diode temperature sensor zones
•Internal local temperature zone
•0.5 °C resolution
•Measures temperatures up to 140 °C
•14-lead TSSOP package

Key Specification

Voltage Measurement Accuracy

±2 % (max)

Temperature Sensor Accuracy

±3 °C (max)

Temperature Range:

  

  • LM40 junction

    0 °C to +85 °C

    Remote Temp Accuracy

    0 °C to +100 °C

Power Supply Voltage

+3.0 V to +3.6 V

Average Power Supply Current

0.5 mA (typ)

Conversion Time (all Channels)

29.6ms to 1456ms

General Description

The LM40 is a hardware monitor that measures 3 temperature zones, 5 voltages and has a single-wire interface compatible with National Semiconductor's SensorPath bus. More...


Applications

•Microprocessor based equipment (Motherboards, Video Cards, Base-stations, Routers, ATMs, Point of Sale, ...)
•Power Supplies
  Typical Application
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Typical Performance

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  Block Diagram
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Datasheet
RoHS Compliance Information Size in KbytesDate Click link below to Download
LM40 Hardware Monitor with Dual Thermal Diodes and SensorPath™ Bus 369 Kbytes 21-May-04 View Online
Download

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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
LM40CIMTTSSOP14NOPB1260RoHS Download Lifetime buyN/A
 
Buy Now 		1K+$1.55rail
of
94		NSZXYTT
LM40
CIMT
16 weeksN/A
LM40CIMTXTSSOP14NOPB1260RoHS Download Lifetime buyN/A
 
Buy Now 		1K+$1.55reel
of
2500		NSZXYTT
LM40
CIMT
16 weeksN/A

Obsolete Parts

Obsolete PartAlternate Part or SupplierSourceLast Time Buy Date
LM40CIMT
NONE
NONE
12/01/2009
LM40CIMTX
NONE
NONE
12/01/2009

General Description

The LM40 is a hardware monitor that measures 3 temperature zones, 5 voltages and has a single-wire interface compatible with National Semiconductor's SensorPath bus. SensorPath data is pulse width encoded, thereby allowing the LM40 to be easily connected to many general purpose micro-controllers. Several National Semiconductor Super I/O products include a fully integrated SensorPath master, that when connected to the LM40 can realize a hardware monitor function that includes limit checking for measured values, autonomous fan speed control and many other functions.

The LM40 measures the temperature of its own die as well as two external devices such as a processor thermal diode or a diode connected transistor. The LM40 can resolve temperatures up to 255°C and down to -256°C. The operating temperature range of the LM40 is 0°C to +125°C. Using [Sigma][Delta] ADC it measures +1.2V, +2.5V, +3.3V, +5V and +12V analog input voltages with internal scaling resistors.The address programming pin allows two LM40s to be placed on one SensorPath bus.

Reliability Metrics

Part Number Process EFR Reject EFR Sample Size PPM * LTA Rejects LTA Device Hours FITS MTTF (Hours)
LM40CIMTCMOS7013906008625005244736730
LM40CIMTXCMOS7013906008625005244736730

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.


[Information as of 6-Jan-2009]