KTD-00782-H KTQ45 family Page 44 of 92
3.12 Fan Connector (FAN_CPU)
The FAN_CPU is used for the connection of the FAN for the CPU.
The FAN_SYS can be used to power, control and monitor a fan for chassis ventilation etc.
The 4pin header supports connection of 3-pin FAN, but it is recommended to use the 4-pin type for optimized
FAN speed control. The 3- or 4-pin mode is set in the BIOS setup menu.
4-pin Mode:
PIN Signal Type Ioh/Iol
CONTROL PWM signal for FAN speed control
SENSE Tacho signal from the fan for supervision. The signals shall be generated by an open
collector transistor or similar. Onboard is a pull-up resistor 4K7 to +12V. The signal has to
be pulsed, typically twice per rotation.
12V +12V supply for fan. A maximum of 2000mA can be supplied from this pin.
GND Power Supply GND signal
3-pin Mode:
PIN Signal Type Ioh/Iol
SENSE Tacho signal from the fan for supervision. The signals shall be generated by an open
collector transistor or similar. Onboard is a pull-up resistor 4K7 to +12V. The signal has to
be pulsed, typically twice per rotation.
12V
+12V supply for fan, can be turned on/off or modulated (PWM) by the chipset.
A maximum of 2000mA can be supplied from this pin.
GND Power Supply GND signal