2000 Fairchild Semiconductor International
www.fairchildsemi.com
Rev. 1.0.0
May. 2000.
1
Features
General
Hysteresis power on reset with delay function
5V, 12V supplies monitoring
Thermal shut down(TSD)
Programmable precision regulator usging minimal
external component
Three state control input to reduce number of PINs
Spindle Motor(SPM)
ASIC based start-up
Internal back-EMF processing
Internal sensorless commutation
Internal SPM speed control with SFLL(Syncronized
Frequency Lock Loop).
Linear SPM current control
Selectable Motor Speed (5400/7200 RPM)
Soft commutation circuitry to reduce acoustic noise
Adjustable brake delay time
Maximum 2A start-up current capability
Internal and external spindle brake
Speed lock indicator output
Voice Coil Motor (VCM)
Intelligent retract (decreased bouncing)
1.2A internal VCM power driver
Selectable transconductance
4V precision reference output
Two PWM input (fine/coarse) for VCM set point
Description
The FAN8621B, is a Bipolar monolithic stand-alone IC,
designed for 12V HDD applications.The internal power
stage consists of vertical PNP and NPN TRs for both SPM
and VCM, thus minimizing voltage drop, and increasing
drive capability up to 2A for SPM and 1.2A for VCM. This
device includes soft commutation drive to reduce audible
noise and intelligent retract function for decreased bouncing.
48-QFPH-1414
Typical Applications
Hard disk drive(HDD)
Ordering Information
Device
Package
Operating Temp.
FAN8621B 48-QFPH-1414
0 ~ 70
C
FAN8621B
12V Spindle Motor and Voice Coil Motor Driver IC
FAN8621B
3
Pin Definitions
Pin Number
Pin Name
IO
Pin Function Description
1
VCNT
A
Speed controller output. Range 3.8V to 0.5V
2
CSOFT
A
Capacitor for soft commutation
3
ADJ
A
Adjust external regulator voltage (VREF)
4
SENSE5
A
5V power line sensing
5
VDD
P
5V power line
6
FG
O
Frequency generation for spindle rotation speed. Typically
1.08KHz (5400RPM)
7
VREF
P
Regulator voltage output. This voltage is controlled by pin 3
voltage
8
CLK
I
System clock. Digital clock input as a time reference
9
HALFVCC
P
1/2 VCC
10
POR
O
Power on reset. H : normal, L: power fail
11
CDLY
A
Define POR delay time
12
GAINSEL
I
Sense amplifier gain selection. H : High gain (8), L : Low gain (2)
13
PWMH
I
Coarse PWM input for VCM set point
14
PWML
I
Fine PWM input for VCM set point
15
CFVCM
A
Output of PWM inputs to voltage converter
16
VCMREF4V
P
4V reference output for VCM
17
CRET
A
Define retract delay time.
18
VCC
P
12V power line
19
FILOUT
A
Filtered output of PWM inputs. This voltage define VCM set point
20
SENSE
A
Non-inverting input of differential amplifier for VCM current
sensing
21
CRET2
A
Power for retract when power down
22
PVCC
P
12V power line for VCM
23
VCM-
A
Negative output terminal of VCM power amplifier
24
RRET
A
Adjust maximum retract current
25
SENSEOUT
A
Output of differential amplifier for VCM current sensing
26
PGND
P
Ground for VCM
27
VCM+
A
positive output terminal of VCM power amplifier
28
ERRIN
A
Inverting input of VCM error amplifier
29
VDD
P
5V power line
30
ERROUT
A
Output of VCM error amplifier
31
SUBGND
P
Ground for spindle motor
32
W
A
Spindle W phase output
FAN8621B
4
Pin Definitions (Continued)
Pin Number
Pin Name
IO
Pin Function Description
33
PCS
A
Spindle current sensing.
34
V
A
Spindle V phase output
35
SUBGND
P
Ground for spindle
36
N
A
Spindle N phase output
37
U
A
Spindle U phase output
38
PVCC
P
12V power line for spindle
39
CCOMP
A
Current controller output. This Voltage define spindle output
current
40
BRAKE
A
Gating signal for external brake
41
CBRAKE
A
Charged back-EMF to supply brake power when power down
42
SENSE12
A
12V power line sensing
43
GND
P
Ground
44
CNTL1
I
Control input for spindle . H: spindle enable, Z: Spindle bias
enable, L: brake
45
CNTL2
I
Start-up clock and soft commutation. H: Start-up clock , L : soft
commutation.
46
CNTL3
I
Control input for VCM. H: VCM enable, Z : VCM disable, L:
retract
47
READY
O
Speed lock indicator when speed is within 0.7% speed error
range. H : speed locked, L: unlocked
48
RPMSEL
I
Target spindle speed selection. L : 5400 rpm, H: 7200 rpm with
5MHz Clock
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