Features Remote diode temperature sensing (2 channels) 8 positive voltage inputs with scaling resistors for monitoring +5 V, +12 V, +3.3 V, +2.5 V, Vccp power supplies directly 2 inputs selectable for fan speed or voltage monitoring 8-bit DAC output for controlling fan speed Chassis Intrusion Detector input WATCHDOG comparison of all monitored values SMBus or I 2C Serial Bus interface compatibility VID0-VID4 or IRQ0-IRQ4 monitoring inputs On chip temperature sensor Description The LM87 is a highly integrated data acquisition system for hardware monitoring of servers, Personal Computers, or virtually any microprocessor-based system. In a PC, the LM87 can be used to monitor power supply voltages, motherboard and processor temperatures, and fan speeds. Actual values for these inputs can be read at any time. Programmable WATCHDOG limits in the LM87 activate a fully programmable and maskable interrupt system with two outputs (INT# and THERM#). The LM87 has an on-chip digital output temperature sensor with 8-bit resolution as well as the capability of monitoring 2 external diode temperatures to 8-bit resolution, an 8 channel analog input ADC with 8-bit resolution and an 8-bit DAC. A channel on the ADC measures the supply voltage applied to the LM87, nominally 3.3 V. Two of the ADC inputs can be redirected to a counter that can measure the speed of up to 2 fans. A slow speed ΣΔ ADC architecture allows stable measurement of signals in an extremely noisy environment. The DAC, with a 0 to 2.5 V output voltage range, can be used for fan speed control. Additional inputs are provided for Chassis Intrusion detection circuits, and VID monitor inputs. The VID monitor inputs can also be used as IRQ inputs if VID monitoring is not required. The LM87 has a Serial Bus interface that is compatible with SMBus and I 2C ™. Key Specification ■  Voltage Monitoring Error ±2 % (max) ■  External Temperature Error ±4 °C (max) ■  Internal Temperature Error     −40 °C to +125 °C ± 3 °C (typ) ■  Supply Voltage Range 2.8 to 3.8 V ■  Supply Current 0.7 mA (typ) ■  ADC and DAC Resolution 8 Bits ■  Temperature Resolution 1.0 °C Applications System Thermal and Hardware Monitoring for Servers, Workstations and PCs Networking and Telecom Equipment Office Electronics Electronic Test Equipment and Instrumentation

Typical Application click for larger image	Block Diagram click for larger image LM87 Block Diagram
Typical Performance click for larger image

Datasheets

Title		Size	Date	Other Language
	LM87 Serial Interface System Hardware Monitor with Remote Diode Temperature Sensing	675 Kbytes	1-Sep-10

Application Notes

Title		Size	Date	Other Language
	AN-2113: Application Note 2113 Applying I2C Compatible Temperature Sensors in Systems with Slow Clock Edges	81 Kbytes	3-May-11

Other Technical Documents

Title		Type	Date
	Multiple Remote Diode Temperature Sensing	App Note	2003-02-17
	Cost Effective Partitioning of IO and Management Functions in PCs - Introduction of SensorPath™ Technology	Technology Edge	2004-01-01

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LM87CIMT/NOPB LM87CIMT RoHS Status	TSSOP	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 424 AVNET-EM Worldwide 15 DIGI-KEY Worldwide 163 FARNELL Europe and Asia 36 MOUSER Worldwide 173 NEWARK Americas 36 RS COMPONENTS Worldwide 9 TAYLOR Americas 1844	$2.49 each at 1K+ pcs	rail of 61
LM87CIMTX/NOPB LM87CIMTX RoHS Status	TSSOP	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 6007 DIGI-KEY Worldwide 0 TAYLOR Americas 6007	$2.49 each at 1K+ pcs	reel of 2500

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 LM87.

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 LM87 is located at RoHS Status.

Part Number(s) (NSID)	Weight (milligrams)	Type	Pins	MSL Rating	Peak Reflow	RoHS Status	CAD Symbols	Models	Package Marking Format
LM87CIMT/NOPB LM87CIMT	83.622 84.002	TSSOP	24	1 1	260 260	Detail	Download	N/A	NSUZXYTTE# LM87CIMT
LM87CIMTX/NOPB LM87CIMTX	83.622 84.003	TSSOP	24	1 1	260 260	Detail	Download	N/A	NSUZXYTTE# LM87CIMT

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 LM87.

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 LM87 is located at RoHS Status.

Design Tools

Title	Size	Date
LMxx - Windows 95/98 VXD drivers with stand alone application for talking to temperature sensors or hardware monitors on a mother board

CAD Symbols and Models Download LM87 CAD Symbols

Models N/A

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM87CIMT	CS065	2	47473	43	0	5527000	1	1568301341
LM87CIMTX	CS065	2	47473	43	0	5527000	1	1568301341

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 LM87.

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 LM87 is located at RoHS Status.