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 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. Key Specification Supply Voltage 3.0V to 3.6V Supply Current 0.8mA (typ) Local Temp Accuracy (includes quantization error) TA=25°C to 125°C ±4.0°C (max) Remote Diode Temp Accuracy (includes quantization error) TA=30°C to 50°C, TD=60°C to 100°C ±3.0°C (max) TA=0°C to 85°C, TD=25°C to 125°C ±4.0°C (max) Applications System Thermal Management (e.g. Laptop, Desktop, Workstations, Server) Electronic Test Equipment Office Electronics

Typical Application click for larger image	Block Diagram click for larger image
Typical Performance click for larger image

Parameters Values 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 bits Resolution degC/LSB 0.125 Supply Max 3.6 Volt Shut down Yes Interrupt Outputs 2 Fault Queue Yes

Datasheets

Title		Size	Date	Other Language
	LM90 ±3°C Accurate, Remote Diode and Local Digital Temperature Sensor with Two-Wire Interface	384 Kbytes	19-Feb-02	日本語

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LM90CIMM/NOPB LM90CIMM RoHS Status	MINI SOIC	Full production Lead Time: 12 weeks	Distributor Region Qty ARROW Worldwide 988 AVNET-EM Worldwide 1000 DIGI-KEY Worldwide 3679 FARNELL Europe and Asia 615 MOUSER Worldwide 1000 NEWARK Americas 615 RS COMPONENTS Worldwide 60 TAYLOR Americas 988	$0.72 each at 1K+ pcs	reel of 1000

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LM90.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LM90 is located at RoHS Status.

Part Number(s) (NSID)	Description	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LM90EVAL	LM90EVAL Evaluation Board	Full production	Distributor Region Qty DIGI-KEY Worldwide 0	$78.00 each	1

National Semiconductor follows the provisions of the Product Stewardship Guide for Customers (CSP-9-111C1) and Banned Substances and Materials of Interest Specification (CSP-9-111S2) for regulatory environmental compliance. Details may be found at: www.national.com/en/packaging/greennopb.html. Lead free products are RoHS compliant.

Lead Free product status is available through the search tool located here

Part Number(s) (NSID)	Weight (milligrams)	Type	Pins	MSL Rating	Peak Reflow	RoHS Status	CAD Symbols	Models	Package Marking Format
LM90CIMM/NOPB LM90CIMM	29.851 30.002	MINI SOIC	8	1 1	260 260	Detail	Download	N/A	ZXTT T11C

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LM90.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LM90 is located at RoHS Status.

Design Tools

Title	Size	Date
SensorEval Software for Thermal Mangement Products

CAD Symbols and Models Download LM90 CAD Symbols

Models N/A

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM90CIMM	CMOS7	0	21301	0	0	1584000	3	449464325

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.

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LM90.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LM90 is located at RoHS Status.