EMC2302 Datasheet, PDF (1/44 Pages) SMSC Corporation – Dual RPM-Based PWM Fan Controller

EMC2302
Dual RPM-Based PWM
Fan Controller
PRODUCT FEATURES
Datasheet
General Description
The EMC2302 is an SMBus compliant fan controller with
up to two 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 EMC2302 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.
Applications
„ Servers
„ Projectors
„ Industrial and Networking Equipment
„ Notebook Computers
Features
„ Two Programmable Fan Control circuits (EMC2302)
— 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
„ CLK Pin can provide a clock source output
„ Available in a 10-pin MSOP Lead-free RoHS
Compliant package
Block Diagram
CLK
TACH1
TACH2
Tach
Measurement
Tachometer
Limit
Registers
PWM1
PWM2
PWM
Drivers
Fan Speed Control Algorithm
Fan Speed Control Algorithm
SMBus
Slave
Protocol
SMCLK
SMDATA
ALERT#
SMSC EMC2302
DATASHEET
Revision 1.1 (10-12-09)