FAN8408D Datasheet, PDF (7/12 Pages) Fairchild Semiconductor – 2 Phase Half Wave BLDC Motor Driver

3. Hall Amplifier Input Block
V
CC
R1
IN+
C1
5
FAN8408D ^C2
R2
6
IN-
Hall
Sensor
R3
FAN8408D
The hall current (IH) is determined by R1, R2 and R3.
IH
=
------------^V----^C-----^C---------------
R1 + R2 + R3
Where, the R2 is the impedance of hall sensor.
An external capacitor, C1, can be used to reduce a power supply noise. In addition, C2 is to remove a noise which is caused in
case the line is long from the hall sensor output to the hall input (pin 5 / 6) of the device.
The input bias voltage of hall amplifier is between 1V and VCC-2V as following figure.
V_CC
V_CC-2V
V_CC / 2
1V
GND
It is recommended that R1 and R3 should have the same value to make the output signal of hall sensor centered as VCC/2.
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