f75334 Feature Integration Technology Inc., f75334 Datasheet - Page 19

• Manufacturer Part Number: f75334
• Description: Performance Controller
• Manufacturer: Feature Integration Technology Inc.

Fan speed count
level of these signals should be set to TTL level, and maximum input voltage cannot be over
5V. If the input signals from the tachometer outputs are over the 5V, the external trimming
circuit should be added to reduce the voltage to obtain the input specification. The normal
circuit and trimming circuits are shown as follows:
Inputs are provided by the signals from fans equipped with tachometer outputs. The
Determine the fan counter according to:
In other words, the fan speed counter has been read from register, the fan speed can be
FAN Out
Fan with Tach Pull-Up to +12V, or Totern-Pole
FAN Out
+12V
GND
+5V
GND
Fan with Tach Pull-Up to +5V, or Totern-Pole
+12V
+5V
Output and Register Attenuator
Output and Register Attenuator
Pull-up resister
4.7K Ohms
22K~30K
Pull-up resister
4.7K Ohms
1K~2.7K
Fan Input
Fan Input
10K
10K
FANIN1
F75334DG
FANIN 1
F75334DG
Count
12
Fig 7-5 / 7-6
Fig 7-7 / 7-8
=
1 ×
5 .
RPM
Connector
10
Connector
FAN
6
FAN
Fan with Tach Pull-Up to +12V, or Totem-Pole Putput
FAN Out
FAN Out
+12V
GND
+5V
GND
+12V
+5V
Totem-Pole Putput and Zener Clamp
Fan with Tach Pull-Up to +5V, or
and Zener Clamp
Pull-up resister < 1K
or totem-pole output
Pull-up resister < 1K
or totem-pole output
3.3V Zener
3.3V Zener
> 1K
> 1K
Fan Input
Fan Input
F75334
FANIN1
F75334DG
FANIN 1
F75334DG
July, 2007
V0.25P