SCH3112I-NE SMSC [SMSC Corporation], SCH3112I-NE Datasheet - Page 390

• Manufacturer Part Number: SCH3112I-NE
• Description: LPC IO with 8042 KBC, Reset Generation, HWM and Multiple Serial Ports
• Manufacturer: SMSC [SMSC Corporation]

LPC IO with 8042 KBC, Reset Generation, HWM and Multiple Serial Ports
Datasheet
3.3V
12V
Fan
470
M
PWMx
0
MMBT2222
Empty
Figure B.2 Fan Drive Circuitry for Low Frequency Option (Apply to PWM Driving One Fan)
3.3V
Tach
10k
TACH
Output
Input
from Fan
D1
IN4148
Note: For fans controlled directly by a PWM, it is suggested to implement
the optional diode (D1) to protect the tachometer input from large voltage
spikes generated by the fan.
Figure B.3 Fan Tachometer Circuitry (Apply to Each Fan)
Rev 0.2 (09-28-04)
374
SMSC SCH311X
DATASHEET