EMC2301
RPM-Based PWM Fan
Controller
PRODUCT FEATURES
General Description
The EMC2301 is an SMBus compliant fan controller with
a PWM fan driver. The fan driver is controlled by a
programmable frequency PWM driver and Fan Speed
Control algorithm that operates in either a closed loop
fashion or as a directly PWM-controlled device.
Each closed loop Fan Speed Control algorithm (FSC)
has the capability to detect aging fans and alert the
system. It will likewise detect stalled or locked fans and
trigger an interrupt.
Additionally, the EMC2301 offers a clock output so that
multiple devices may be chained and slaved to the
same clock source for optimal performance in large
distributed systems.
Datasheet
Features
Programmable Fan Control circuit (EMC2301)
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4-wire fan compatible
High speed PWM (26 kHz)
Low speed PWM (9.5Hz - 2240 Hz)
Optional detection of aging fans
Fan Spin Up Control and Ramp Rate Control
Alert on Fan Stall
Watchdog Timer
RPM-based fan control algorithm
— 0.5% accuracy from 500 RPM to 16k RPM (external
crystal oscillator)
— 1% accuracy from 500 RPM to 16k RPM (internal clock)
SMBus 2.0 Compliant
— SMBus Alert compatible
Applications
Servers
Projectors
Industrial and Networking Equipment
Notebook Computers
CLK Pin can provide a clock source output
Available in an 8-pin MSOP Lead-free RoHS
Compliant package
Block Diagram
CLK
TACH
Tach
Measurement
Tachometer
Limit
Registers
SMBus
Slave
Protocol
SMCLK
SMDATA
ALERT#
PWM
PWM
Drivers
Fan Speed Control Algorithm
SMSC EMC2301
DATASHEET
Revision 1.1 (10-12-09)
SMSC [ SMSC CORPORATION ]
