Fan Control Device with Hardware Monitoring and Acoustic Noise Reduction Features
Datasheet
3.3V
10k
Tach
TACH
Input
Output
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)
Remote Diode +
External Temperature
Sensing Diode
2.2nF
(MMBT3904)
Remote Diode -
Figure B.4 Remote Diode (Apply to Remote2 Lines)
Notes:
1. 2.2nF cap is optional and should be placed close to the EMC6D102 if used.
2. The voltage at PWM3 must be at least 2.0V to avoid triggering Address Enable.
3. The Remote Diode + and Remote Diode - tracks should be kept close together, in parallel with
grounded guard tracks on each side. Using wide tracks will help to minimize inductance and
reduce noise pickup. A 10 mil track minimum width and spacing is recommended. See Figure B.5,
"Suggested Minimum Track Width and Spacing".
.
10 mil.
10 mil.
GND
10 mil.
10 mil.
D+
10 mil.
10 mil.
D-
10 mil.
GND
Figure B.5 Suggested Minimum Track Width and Spacing
Revision 0.4 (04-05-05)
SMSC EMC6D102
DATA8S6HEET
SMSC [ SMSC CORPORATION ]
