MIC284 Micrel, Inc.
MIC284
Two-Zone Thermal Supervisor
General Description
The MIC284 is a versatile digital thermal supervisor capable of
SilentSense
measuring temperature using its own internal sensor and an
inexpensive external sensor or embedded silicon diode such Features
as those found in the Intel Pentium III CPU. A 2-wire serial
Optimized for CPU Thermal Supervision in Computing
2
interface is provided to allow communication with either I C
Applications
or SMBus masters. Features include an open-drain over-
Measures Local and Remote Temperature
temperature output with dedicated registers for implementing
Sigma-Delta ADC for 8-Bit Temperature Results
fan control or over-temperature shutdown circuits.
2-Wire SMBus-compatible Interface
Interrupt status and mask bits are provided for reduced soft- Programmable Thermostat Settings for both Internal and
ware overhead. The open-drain interrupt output pin can be External Zones
used as either an overtemperature alarm or a thermostatic Open-Drain Interrupt Output Pin
control signal. A programmable address pin permits two Open-Drain Over Temperature Output Pin for Fan Con-
devices to share the bus. (Alternate base addresses avail- trol or Hardware Shutdown
able-contact Micrel.) Superior performance, low power and Interrupt Mask and Status Bits
small size makes the MIC284 an excellent choice for the most Low Power Shutdown Mode
demanding thermal management applications. The MIC284 Failsafe response to diode faults
is part of the SilentSense family of thermal supervisors. 2.7V to 5.5V Power Supply Range
8-Lead SOIC and MSOP Packages
Data sheets and support documentation can be found on
Micrels web site at www.micrel.com.
Applications
Desktop, Server and Notebook Computers
Power Supplies
Test and Measurement Equipment
Wireless Systems
Networking/Datacom Hardware
Typical Application
3.3V
0.1F
4 10k
pull-ups
MIC284
DATA VDD
FROM
SERIAL BUS
CLK T1
REMOTE
HOST DIODE
/INT A0
2200pF
OVER-TEMP
/CRIT GND
SHUTDOWN
2-Channel SMBus Temperature Measurement System
SMBus and Pentium III are trademarks of Intel Corporation.
2
I C 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 (408) 944-0800 fax + 1 (408) 474-1000 MIC284 Micrel, Inc
Ordering Information
Part Number Base Address (*) Junction Temp. Range Package Availability
Standard Pb-Free
MIC284-0BM MIC284-0YM 100 100x -55C to +125C 8-Lead SOIC
MIC284-1BM MIC284-1YM 100 101x -55C to +125C 8-Lead SOIC Contact Factory
MIC284-2BM MIC284-2YM 100 110x -55C to +125C 8-Lead SOIC Contact Factory
MIC284-3BM MIC284-3YM 100 111x -55C to +125C 8-Lead SOIC Contact Factory
MIC284-0BMM MIC284-0YMM 100 100x -55C to +125C 8-Lead MSOP
MIC284-1BMM MIC284-1YMM 100 101x -55C to +125C 8-Lead MSOP Contact Factory
MIC284-2BMM MIC284-2YMM 100 110x -55C to +125C 8-Lead MSOP Contact Factory
MIC284-3BMM MIC284-3YMM 100 111x -55C to +125C 8-Lead MSOP Contact Factory
* The least-signicant bit of the slave address is determined by the state of the A0 pin.
Pin Conguration
DATA 1 8 VDD
CLK 2 7 A0
/INT 3 6 T1
GND 4 5 /CRIT
Pin Description
Pin Number Pin Name Pin Function
1 DATA Digital I/O: Open-drain. Serial data input/output.
2 CLK Digital Input: The host provides the serial bit clock on this input.
3 /INT Digital Output: Open-drain. Interrupt or thermostat output.
4 GND Ground: Power and signal return for all IC functions.
5 /CRIT Digital Output: Open-Drain. Over-temperature indication
6 T1 Analog Input: Connection to remote temperature sensor (diode junc-
tion)
7 A0 Digital Input: Slave address selection input. See Table 1. MIC284 Slave
Address Settings.
8 VDD Analog Input: Power supply input to the IC.
MIC284 2 September 2005