MIC280
Micrel
MIC280
Precision IttyBitty™ Thermal Supervisor
REV. 11/04
General Description
The MIC280 is a digital thermal supervisor capable of measur-
ing its own internal temperature and that of a remote PN junc-
tion. The remote junction may be an inexpensive commodity
transistor, e.g., 2N3906, or an embedded thermal diode such
as found in Intel Pentium* II/III/IV CPUs, AMD Athlon* CPUs,
and Xilinx Virtex* FPGA's. A 2-wire SMBus* 2.0 compatible
serial interface is provided for host communication. Remote
temperature is measured with ±1°C accuracy and 9-bit to
12-bit resolution (programmable). Independent high, low, and
over-temperature thresholds are provided for each zone.
The advanced integrating A/D converter and analog front-end
reduce errors due to noise for maximum accuracy and mini-
mum guardbanding. The interrupt output signals temperature
events to the host, including data-ready and diode faults.
Critical device settings can be locked to prevent changes and
insure failsafe operation. The clock, data, and interrupt pins
are 5V-tolerant regardless of the value of V
DD
. They will not
clamp the bus lines low even if the device is powered down.
Superior accuracy, failsafe operation, and small size make
the MIC280 an excellent choice for the most demanding
thermal management applications.
Features
• Measures local and remote temperature
• Highly accurate remote sensing
±1°C max., 60°C to 100°C
• Superior noise immunity for reduced temperature guard-
bands
• 9-bit to 12-bit temperature resolution for remote zone
• Fault queues to further reduce nuisance tripping
• Programmable high, low, and over-temperature thresh-
olds for each zone
• SMBus 2 compatible serial interface including device
timeout to prevent bus lockup
• Voltage tolerant I/O’s
• Open-drain interrupt output pin - supports SMBus Alert
Response Address protocol
• Low power shutdown mode
• Locking of critical functions to insure failsafe operation
• Failsafe response to diode faults
• Enables ACPI compliant thermal management
• 3.0V to 3.6V power supply range
• IttyBitty™ SOT23-6 package
Applications
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•
•
•
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Desktop, server and notebook computers
Printers and copiers
Test and measurement equipment
Thermal supervision of Xilinx Virtex FPGA's
Wireless/RF systems
Intelligent power supplies
Datacom/telecom cards
Typical Application
3V to 3.6V
3
×
10k
5
TO
SERIAL BUS
HOST
4
6
MIC280
DATA
CLK
/INT
VDD
T1
GND
1
3
2
0.1µF
ceramic
1800pF
2N3906/�½
CPU DIODE
MIC280 Typical Application
IttyBiity is a trademark of Micrel, Inc.
*All trademarks are the property of their respective owners.
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
May 2006
1
MIC280
MICREL [ MICREL SEMICONDUCTOR ]
