Multiple RPM-Based PWM Fan Controller for Five Fans
Datasheet
Table 1.1 Pin Description for EMC2305 (continued)
PIN NUMBER
6
PIN NAME
TACH1
PIN FUNCTION
Open drain tachometer input for Fan 1-
requires pull-up resistor
Push-Pull PWM output driver for Fan 2
7
PWM2
Open Drain PWM output driver for Fan 2
8
TACH2
Open drain tachometer input for Fan 2 -
requires pull-up resistor
Push-Pull PWM output driver for Fan 3
9
PWM3
Open Drain PWM output driver for Fan 3
10
TACH3
Open drain tachometer input for Fan 3 -
requires pull-up resistor
Clock input for tachometer measurement
11
CLK
Push Pull Clock output to other fan
controllers to synchronize Fan Speed
Control
Active low interrupt - requires external
pull-up resistor.
Push-Pull PWM output driver for Fan 4
13
PWM4
Open Drain PWM output driver for Fan 4
14
TACH4
Open drain tachometer input for Fan 4 -
requires pull-up resistor
Push-Pull PWM output driver for Fan 5
15
PWM5
Open Drain PWM output driver for Fan 5
16
Bottom Pad
TACH5
GND
Open drain tachometer input for Fan 5 -
requires pull-up resistor
Ground
OD (5V)
DI (5V)
Power
OD (5V)
DI (5V)
DO
OD (5V)
DI (5V)
DI (5V)
DO
OD (5V)
DI (5V)
DO
PIN TYPE
DI (5V)
DO
12
ALERT#
OD (5V)
DO
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.
Revision 1.1 (10-12-09)
8
SMSC EMC2305
DATASHEET
SMSC [ SMSC CORPORATION ]
