LM87 - Serial Interface System Hardware Monitor with Remote Diode Temperature Sensing

LM87 - Serial Interface System Hardware Monitor with Remote Diode Temperature Sensing from the PowerWise® Family

Datasheet	Packaging	Samples & Pricing	Reliability	Design Tools	Application Notes	Knowledge Base

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 I²C Serial Bus interface compatibility
•	VID0-VID4 or IRQ0-IRQ4 monitoring inputs
•	On chip temperature sensor

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

General Description

The LM87 is a highly integrated data acquisition system for hardware monitoring of servers, Personal Computers, or virtually any microprocessor-based system. More...

Applications

•	System Thermal and Hardware Monitoring for Servers, Workstations and PCs
•	Networking and Telecom Equipment
•	Office Electronics
•	Electronic Test Equipment and Instrumentation

Typical Application

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Parameters Values

Temp Resolution 8-bit/1degC

Remote Diode Thermal Sensors 2

TruTherm(TM) Beta Compensation No

Analog Inputs 7 to 3, V+

ADC Resolution 8 bits

Fan Speed Inputs 4

Fan Control Output(s) 1 DAC

Fan Control Method Undefined

VID Inputs 5

Dynamic VID VCCP Monitoring Undefined

Bidirectional PROCHOT Support Undefined

GPIOs CI, RESET

Interrupt Outputs 1

Reference Voltage Undefined

Temperature Accuracy (+/-) 4 deg C

Temperature Min -40 deg C

Temperature Max 125 deg C

Interface Type 2-Wire Serial

Supply Min 2.8 Volt

Supply Max 3.8 Volt

Quiescent Current 2 mA

Resolution 8 bits

Temperature Accuracy (+/-) 3 deg C

Automotive Yes

PowerWise Yes

Typical Performance

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Additional Resources

Design Tools

Application Notes

Block Diagram

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Datasheet

RoHS Compliance Information	Size in Kbytes	Date
LM87 Serial Interface System Hardware Monitor with Remote Diode Temperature Sensing	470 Kbytes	10-Dec-03	Download

If you have trouble printing or viewing PDF file(s), see Printing Problems.

Package Availability, Models, Samples & Pricing

Part Number

Package

Factory Lead Time

Models

Samples &
Electronic
Orders

Budgetary Pricing

Std
Pack
Size

Package
Marking
Format

Type

Pins

Spec.

MSL
Rating

Peak
Reflow

RoHS
Report

CAD
Symbols

Weeks

Qty

$US each

LM87CIMT

TSSOP

NOPB
STD

1
1

260
260

RoHS

Download

Full production

N/A

1K+

$2.49

rail
of
61

NSUZXYTTE#
LM87CIMT

16 weeks

1000

LM87CIMTX

TSSOP

NOPB
STD

1
1

260
260

RoHS

Download

Full production

N/A

1K+

$2.49

reel
of
2500

NSUZXYTTE#
LM87CIMT

6 weeks

7500

General 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 [Sigma][Delta] 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 I²C™.

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM87CIMT	CS065	2	38968	52	0	4402000	1	1249079519
LM87CIMTX	CS065	2	38968	52	0	4402000	1	1249079519

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.

Design Tools

Title	Size in Kbytes	Date
LMxx - Windows 95/98 VXD drivers with stand alone application for talking to temperature sensors or hardware monitors on a mother board	1366 Kbytes	28-Jul-2003	View	Download

If you have trouble printing or viewing PDF file(s), see Printing Problems.

More Application Notes

Title	Size in Kbytes	Date
AN-1155: Application Note 1155 A Simple Software I2C Routine for the COP8	82 Kbytes	15-May-04	Download
AN-1260: Application Note 1260 Autonomous Fan Control for Processor Systems Using the LM85	74 Kbytes	10-Mar-04	Download
AN-1262: Application Note 1262 Four-Speed Fan Control Using Simple Remote Diode Temperature Sensor	70 Kbytes	1-Oct-02	Download

If you have trouble printing or viewing PDF file(s), see Printing Problems.

[Information as of 8-Nov-2009]