RPM-Based PWM Fan Controller
Datasheet
Chapter 1 Pin Description
SMDATA
SMCLK
VDD
GND
1
2
3
4
EMC2301
8-MSOP
8 ALERT#
7 CLK
6
TACH
5 PWM
Figure 1.1 EMC2301 Pin Diagram (8 pin MSOP)
Table 1.1 Pin Description for EMC2301
PIN NUMBER
1
2
3
4
5
PIN NAME
SMDATA
SMCLK
VDD
GND
PWM
Open Drain PWM output driver for the Fan
6
TACH
Open drain tachometer input for the Fan -
requires pull-up resistor
Clock input for tachometer measurement
7
CLK
Push-Pull Clock output to other fan
controllers to synchronize Fan Speed
Control
Active low interrupt - requires external
pull-up resistor.
OD (5V)
DI (5V)
DI (5V)
DO
PIN FUNCTION
SMBus data input/output - requires
external pull-up resistor
SMBus clock input - requires external
pull-up resistor
Power Supply
Ground
Push-Pull PWM output driver for the Fan
PIN TYPE
DIOD (5V)
DI (5V)
Power
Power
DO
8
ALERT#
OD (5V)
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.
SMSC EMC2301
7
Revision 1.1 (10-12-09)
DATASHEET
SMSC [ SMSC CORPORATION ]
