EMC2305
Multiple RPM-Based
PWM Fan Controller for
Five Fans
PRODUCT FEATURES
General Description
The EMC2305 is an SMBus compliant fan controller with
up to five independently controlled PWM fan drivers.
Each 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.
The 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 EMC2305 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
Five Programmable Fan Control circuits (EMC2305)
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—
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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
Up to 3 Selectable Default Fan Speeds
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
— Up to 6 selectable SMBus addresses
— SMBus Alert compatible
Applications
Servers
Projectors
Industrial and Networking Equipment
Notebook Computers
CLK Pin can provide a clock source output
Available in a 16-pin 4mm x 4mm QFN Lead-free
RoHS Compliant package
Block Diagram
CLK
TACH1
TACH2
TACH3
TACH4
TACH5
PWM1
PWM2
PWM3
PWM4
PWM5
PWM
Drivers
Fan Speed Control Algorithm
Fan Speed Control Algorithm
Fan Speed Control Algorithm
Fan Speed Control Algorithm
Fan Speed Control Algorithm
Tach
Measurement
Tachometer
Limit
Registers
SMBus
Slave
Protocol
ADDR_SEL
SMCLK
SMDATA
ALERT#
SMSC EMC2305
DATASHEET
Revision 1.1 (10-12-09)
SMSC [ SMSC CORPORATION ]
