September 29, 2000

1

MIC284

MIC284

Micrel

MIC284

Two-Zone Thermal Supervisor

Advance Information

Typical Application

CLK

FROM

SERIAL BUS

HOST

OVER-TEMP

SHUTDOWN

REMOTE

DIODE

2200pF

0.1

µF

MIC284

/INT

/CRIT

3.3V

DATA

4

× 10k

pull-ups

VDD

T1

A0

GND

2-Channel SMBus Temperature Measurement System

Features

• Optimized for CPU Thermal Supervision in Computing

Applications

• Measures Local and Remote Temperature

• Sigma-Delta ADC for 8-Bit Temperature Results

• 2-Wire SMBus-compatible Interface

• Programmable Thermostat Settings for both Internal and

External Zones

• Open-Drain Interrupt Output Pin

• Open-Drain Over Temperature Output Pin for Fan

Control or Hardware Shutdown

• Interrupt Mask and Status Bits

• Low Power Shutdown Mode

• Failsafe response to diode faults

• 2.7V to 5.5V Power Supply Range

• 8-Lead SOIC and MSOP Packages

Applications

• Desktop, Server and Notebook Computers

• Power Supplies

• Test and Measurement Equipment

• Wireless Systems

• Networking/Datacom Hardware

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com

General Description

The MIC284 is a versatile digital thermal supervisor capable

of measuring temperature using its own internal sensor and

an inexpensive external sensor or embedded silicon diode

such as those found in the Intel Pentium III* CPU. A 2-wire

serial interface is provided to allow communication with either

over-temperature output with dedicated registers for imple-

menting fan control or over-temperature shutdown circuits.

Interrupt status and mask bits are provided for reduced

software overhead. The open-drain interrupt output pin can

be used as either an overtemperature alarm or a thermostatic

control signal. A programmable address pin permits two

devices to share the bus. (Alternate base addresses avail-

able-contact Micrel.) Superior performance, low power and

small size makes the MIC284 an excellent choice for the most

demanding thermal management applications.

*SMBus and Pentium III are trademarks of Intel Corporation.

Ordering Information

Part Number

Junction Temp. Range

Package

Notes

MIC284-0BM

100 100x

–55

°C to +125°C

8-Lead SOP

MIC284-1BM

100 101x

–55

°C to +125°C

8-Lead SOP

Contact Factory

MIC284-2BM

100 110x

–55

°C to +125°C

8-Lead SOP

Contact Factory

MIC284-3BM

100 111x

–55

°C to +125°C

8-Lead SOP

Contact Factory

MIC284-0BMM

100 100x

–55

°C to +125°C

8-Lead MSOP

MIC284-1BMM

100 101x

–55

°C to +125°C

8-Lead MSOP

Contact Factory

MIC284-2BMM

100 110x

–55

°C to +125°C

8-Lead MSOP

Contact Factory

MIC284-3BMM

100 111x

–55

°C to +125°C

8-Lead MSOP

Contact Factory

* The least-significant bit of the slave address is determined by the state of the A0 pin.