MIC284_05 Datasheet, PDF (1/20 Pages) Micrel Semiconductor – Two-Zone Thermal Supervisor

MIC284
MIC284
Micrel, Inc.
Two-Zone Thermal Supervisor
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 I²C™
or SMBus™ masters. Features include an open-drain over-
temperature output with dedicated registers for implementing
fan control or over-temperature shutdown circuits.
Interrupt status and mask bits are provided for reduced soft-
ware 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. The MIC284
is part of the SilentSense™ family of thermal supervisors.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
SilentSense™
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 Con-
trol 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
Typical Application
3.3V
4  10k
pull-ups
FROM
SERIAL BUS
HOST
OVER-TEMP
SHUTDOWN
MIC284
DATA
VDD
CLK
T1
/INT
A0
/CRIT
GND
0.1F
2200pF
REMOTE
DIODE
2-Channel SMBus Temperature Measurement System
SMBus and Pentium III are trademarks of Intel Corporation.
I²C is a trademark of Philips Electronics, N.V.
SilentSense is a trademark of Micrel, Inc.
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com
September 2005
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MIC284