RPM-Based PWM Fan Controller

Datasheet

SMSC EMC2301

7

Revision 1.1 (10-12-09)

DATASHEET

Chapter 1 Pin Description

The pin types are described in detail below. All pins labeled with (5V) are 5V tolerant.

APPLICATION NOTE: For the 5V tolerant pins that have a pull-up resistor, the voltage difference between VDD and

the 5V tolerant pad must never be more than 3.6V.

Figure 1.1 EMC2301 Pin Diagram (8 pin MSOP)

Table 1.1 Pin Description for EMC2301

PIN NUMBER

PIN NAME

PIN FUNCTION

PIN TYPE

1SMDATA

SMBus data input/output - requires

external pull-up resistor

DIOD (5V)

2SMCLK

SMBus clock input - requires external

pull-up resistor

DI (5V)

3

VDD

Power Supply

Power

4

GND

Ground

Power

5PWM

Push-Pull PWM output driver for the Fan

DO

Open Drain PWM output driver for the Fan

OD (5V)

6TACH

Open drain tachometer input for the Fan -

requires pull-up resistor

DI (5V)

7CLK

Clock input for tachometer measurement

DI (5V)

Push-Pull Clock output to other fan

controllers to synchronize Fan Speed

Control

DO

8ALERT#

Active low interrupt - requires external

pull-up resistor.

OD (5V)

EMC2301

8-MSOP

1

2

3

8

7

6

VDD

SMCLK

PWM

SMDATA

CLK

GND

TACH

ALERT#

4

5