FAN8422G View Datasheet(PDF) - Fairchild Semiconductor
Part Name
Description
View to exact match
FAN8422G Datasheet PDF : 10 Pages
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FAN8422G
Application Information
1. Chip Enable
This function turns on or off all blocks by low or high signal (active low).
2. U, V And W Phase Output Amp
These ampilifiers drive three phase outputs - U, V, and W which have 120 degree phase differences with each other. The three
phase waveforms are made with the two hall sensor signals by synthesizing the third phase signal.
3. Speed Control Part
This function compares the real motor rotation frequency with the 300 or 360Hz pulse divided from 1MHz clock pulse for
removing speed error when the motor is ’on’ and speed error is detected by PLL. The speed error is sent to the charge pump,
which repeats charging and discharging according to the error level. The charge pump output controls the output current to
keep the rotational speed stable.
4. Sensorless Index Signal Generation
FAN8422G can make index signals without an index hall sensor by special rotor magnetization.
Typical Application Circuits
DISK_IN
W_P
SW1
+5V
220nF
1
1
H_D
LED
CE
1MHz
RPM_SEL
INDEX
100
SW2
100nF
47nF
HU
HV
47nF
U INPUT(+)
20
U INPUT(−)
19
V INPUT(+)
26
17 16
28
U PHASE OUTPUT U
25
V PHASE OUTPUT V
24
W PHASE OUTPUT W
22
V INPUT(−)
27
HALL BIAS
29
PHASE COMPENSATION
+5V
16
1.8M
AGC
10k
2
CE
7
FG_INPUT(+)
INDEX OUTPUT
FAN8422G 6
INDEX PULSE WIDTH
3
100nF
30
FG_INPUT(-)
CHARGE PUMP OUTPUT
13
1
FG ZERO CROSS
10
10nF
100nF
56k
4
VOLTAGE REGULATOR
5
23
INDEX BURST
8
VR
14 12
9
47nF
330k
47k
8
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