SI9961ACY Vishay, SI9961ACY Datasheet - Page 4

• Manufacturer Part Number: SI9961ACY
• Description: IC, MOTOR DRIVER VOICE COIL 1.8A SOIC-24
• Manufacturer: Vishay
• Type: Voice Coil Motor Driverr

Specifications of SI9961ACY

• Motor Type: Voice Coil
• No. Of Outputs: 2
• Output Current: 1.8A
• Output Voltage: 9.1V
• Supply Voltage Range: 4.5V To 5.5V
• Driver Case Style: SOIC
• No. Of Pins: 24
• Operating Supply Voltage: - 0.3 V to + 16 V
• Supply Current: 13 mA
• Mounting Style: SMD/SMT
• Package / Case: SO-24
• Operating Temperature: 0 C to + 70 C
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Si9961A
Vishay Siliconix
APPLICATIONS
Introduction
The Si9961A Voice Coil Motor (VCM) driver integrates the
active feedback and drive components of a head-positioning
servo loop for high-performance hard-disk applications. The
Si9961A operates from a 12-V ("10%) power supply and
delivers 1 A of steady-state output current. This device is made
possible by a power IC process which combines bipolar,
CMOS and complimentary DMOS technologies. CMOS logic
and linear components minimize power consumption, bipolar
front-ends on critical amplifiers provide necessary accuracy,
and complimentary (p- and n-channel) DMOS devices allow
the transconductance output amplifier to operate from ground
to V
voltage ratios may be digitally selected to optimize gain for
both seek and track following modes, to maximize system
accuracy for a given DAC resolution. An undervoltage lockout
circuit monitors the V+ supply and generates a fault signal to
trigger an orderly head-retract sequence at a voltage level
sufficient to allow the spindle motor’s back EMF-generated
voltage to supply the necessary head parking energy. Head
retract can also be commanded via a separate RETRACT
input. VCM current during retract can be user programmed
with a single external resistor. External components are limited
to R/C filter components for loop compensation and the
resistors that are required to program gain, retract current, and
the load current sense.
www.vishay.com
4
GAIN SELECT
PIN CONFIGURATION AND ORDERING INFORMATION
I
SENSE
RETRACT
EXT V
DD
ENABLE
FAULT
V
. Two user-programmable, current feedback/input
R
OUT
REF−
R
I
V
RET
REF
INH
INL
V+
CC
10
11
12
1
2
3
4
5
6
7
8
9
(Wide Body)
24-Pin SOIC
Top View
24
23
22
21
20
19
18
17
16
15
14
13
R
IA2−
OA2
I
SOURCE B
OUTPUT B
V
OUTPUT A
GND
SOURCE A
GND
I
SENSE
SENSE
DD
FB
(Spindle Supply)
(IN)−
(IN)
+
User-Programmable Gains
During linear operation, the transconductance amplifiers’
gains (input voltage at V
by external resistors R
gain input. After selecting a value for R
the desired VCM current level, the High and Low feedback
gain ratios may be determined by the following:
Where R
Input offset current may then be calculated as:
Where R
Part Number
Si9961ACY
Si9961ACY-T1
High Gain +
Low Gain +
I
OS
+
4 R
S
IN
1
= R
S
= R
ORDERING INFORMATION
SA
R
R
R
R
3
Si9961ACY-T1—E3
5
4
Lead (Pb)-Free
5
3
or R
Part Number
= R
4 R
R
4 R
4
SB
1
S
1
3
S
R
IN
S
) R
! R
IN
vs. VCM current, in Figure 1) are set
V
OSA2
IN
5
(GAIN SELECT Input = High)
(GAIN SELECT Input = Low)
, R
SA
) 5 V
Temperature
, and R
SA
0 to 70_C
0 to 70_C
S-40845—Rev. H, 03-May-04
Range
IAS3
Document Number: 70014
and R
SB
and selected by
SB
that will yield
(Wide Body)
Package
SOIC-24
SOIC-24