EMC2303-1-KP-TR Standard Microsystems (SMSC), EMC2303-1-KP-TR Datasheet - Page 17

• Manufacturer Part Number: EMC2303-1-KP-TR
• Manufacturer: Standard Microsystems (SMSC)

Specifications of EMC2303-1-KP-TR

• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (min): 3V
• Operating Supply Voltage (max): 3.6V
• Operating Temp Range: -40C to 125C
• Operating Temperature Classification: Automotive
• Mounting: Surface Mount
• Pin Count: 12
• Lead Free Status / RoHS Status: Compliant

Multiple RPM-Based PWM Fan Controller for Three Fans
Datasheet
Chapter 4 Product Description
SMSC EMC2303
4.1
MCU
The EMC2303 is an SMBus compliant fan controller with three programmable frequency PWM fan
drivers. The fan drivers can be operated using two modes: the RPM-based Fan Speed Control
Algorithm or the direct fan drive setting.
Figure 4.1
The EMC2303 has two modes of operation for each fan driver. Each mode of operation uses the Ramp
Rate control and Spin Up Routine.
1. Direct Setting Mode - in this mode of operation, the user directly controls the fan drive setting.
2. Fan Speed Control Mode (FSC) - in this mode of operation, the user determines a target
Fan Control Modes of Operation
Updating the Fan Driver Setting Register (see
Ramp Rate control is optional and enabled via the EN_RRC bits.
tachometer count and the PWM drive setting is automatically updated to achieve this target speed.
The algorithm uses the Spin Up Routine and has user definable ramp rate controls.
Whenever the Direct Setting Mode is enabled, the current drive will be changed to what was
last written into the Fan Driver Setting Register.
This mode is enabled setting the EN_ALGO bit in the Fan Configuration Register.
shows a system diagram of the EMC2303.
tachometer
Circuit
Drive
Figure 4.1 System Diagram of EMC2303
3.3V
SMCLK
SMDATA
ALERT#
TACH1
PWM1
ADDR_SEL
GND
DATASHEET
EMC2303
VDD
17
Section
TACH3
TACH2
PWM3
PWM2
CLK
5.7) will instantly update the PWM fan drive.
32.768KHz Clock
Input or Output
Circuit
Circuit
Drive
Drive
tachometer
tachometer
Revision 1.2 (03-22-10)