VISHAY Si9961 Datasheet

12-V Voice Coil Motor Driver

FEATURES

D 1.8-A H-Bridge Output
D Class B Linear Operation
D Externally Programmable Gain and

Bandwidth

DESCRIPTION

The Si9961 is a linear actuator (voice coil motor) driver suitable
for use in disk drive head positioning systems. The Si9961
contains all of the power and control circuitry necessary to
drive the VCM that is typically found in 3
drives and optical disk drives. The driver is capable of
delivering 1.8 A at a nominal supply of 12 V.

The Si9961 provides all necessary functions including a motor
current sense amplifier, a loop compensation amplifier and a
power amplifier featuring four complementary MOSFETs in a
H-bridge configuration. The output crossover protection
ensures no cross-conducting current and true Class B

D Undervoltage Head Retract
D Programmable Retract Current
D Low Standby Current

1

/2-inch hard disk

Si9961

Vishay Siliconix

D Rail-to-Rail Output Swing
D Single 12-V Supply
D System Voltage Monitor with Fault Output

operation during linear tracking. Externally programmable
gain switch at the input summing junction increases the
resolution and dynamic range for a given DAC. The head
retract circuitry can be activated by either an undervoltage
condition or an external command. An external resistor is
required to set the VCM current during retract.

The Si9961 is constructed on a self-isolated BiC/DMOS power
IC process. The IC is available in 24-pin SO package for
operation over the commercial, C suffix (0 to 70_C)
temperature range.

FUNCTIONAL BLOCK DIAGRAM

V

CC

IA2–

I

RET

OA2

4
5

23

V

R

9
6

11

22

10

A2

–

+

Acceleration Error

V

FAULT

RETRACT

Enable

GAIN

SELECT

R

EXT

V

REFVREF–

V

8 R

+

–

Retract
Control

–

+

7 R

A3

R

A4

A5

–

+

V+

818712

Voltage
Monitor

R

V

R

R

Q1

Q2

V

DD

Q3

17

OUTPUT

A

OUTPUT

19

Q4

B

Document Number: 70014
S-20883—Rev. G, 24-Jun-02

R

INHRINL

20161415211332421

I

R

FB

SENSE

OUT

I

SENSE

IN+

I

SENSE

IN–

GND

SA SB

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Si9961

Vishay Siliconix

ABSOLUTE MAXIMUM RATINGS

Voltages Referenced to Common Pin

V+ Supply Range –0.3 V to 16 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Pin (FAULT

) –0.3 V to VCC + 0.3 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Pin (Output A & B, Source A & B) –0.3 V to V

Pin (All Others) –0.3 V to V+ + 0.3 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Maximum Clamp Current

Output A, Output B (Pulsed 10 ms at 10% duty cycle) "1.8 A. . . . . . . . . . . .

Pin (All Others) "20 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Storage Temperature –65 to 150_C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DD

+ 0.3 V. . . . . . . . . . . . . . . .

Operating Temperature 0 to 70_C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Junction Temperature (T
Power Dissipation (Package)

24-Pin SOIC

b

Thermal Impedance (

24-Pin SOIC 40_C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Notes
a. Device mounted with all leads soldered or welded to PC board.
b. Derate 25 mW/_C above 25_C.

) 150_C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

J

a

a

)

JA

3.125 W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SPECIFICATIONS

T est Conditions

Unless Otherwise Specified

V+ = 12 V "10%, VDD = 11.6 V "10%

V

Parameter Symbol

= 5 V "10%, V

CC

V

REF

= GND = 0 V

REF–

= 5 V "5%

Min

Bridge Outputs (A4, A5)

High Level Output Voltage V
Low Level Output Voltage V
Clamp Diode Voltage V

OH
OL
CL

Amplifier Gain Output V
Dynamic Crossover Current Measured at V
Slew Rate SR 1 V/S
Small Signal Bandwidth (–3 dB) 0.2 MHz
Input Deadband –60 60 mV

IOH = 1.0 A, VDD = 10.2 V, OA2= V

IOL = –1.0 A, OA2 = V

REF

"1 V 8.0 9.1

REF

"1 V 0.6 1.1

IF = 1.0 A, ENABLE = High 2.5

= V

RANGE

"2 V 12 16 18 V/V

REF

DD

A2, Loop Compensation Amplifier

Input Offset Voltage V
Input Bias Current I
Unity Gain Bandwidth R
Slew Rate SR 1 V/s
Power Supply Rejection Ratio PSRR @ 10 kHz 50
Open Loop Voltage Gain A
Output Voltage Swing V

OS

B

VOL

Gain Select = High, IA

= 10 k, C

LOAD

O

R

LOAD

LOAD

= 10 k to V

–

= 5 V –50 50 nA

2

= 100 pF to V

REF

REF

V

REF

A3, Current Sense Amplifier

Input Offset Voltage V
Input Impedance R
Small Signal Bandwidth (–3 dB) R
Common Mode Rejection Ratio CMRR @ 5 kHz 50 dB
Slew Rate SR 2 V/s
Gain 3.9 4 4.1 V/V
Input Common-Mode Voltage Range V
Output Voltage Swing V

OS

CM

I

IN

LOAD

IN+ to I

SENSE

= 10 k, C

LOAD

IN– 5 k

SENSE

= 100 pF to V

REF

T o GND –0.3 2

R

O

LOAD

= 10 k, C

= 100 pF to V

LOAD

REF

V

REF

Supply

I

CC Static, No Load

Supply Current (Normal)

I

V+

I

DD

RETRACT = High 2 5

ENABLE = Low

Limits

C Suffix 0 to 70_C

b

TypaMaxbUnit

10 mA

–8 8 mV

1 MHz

80

–2 V

–5 5 mV

1 MHz

–2 V

5 13

REF

REF

0.01

+2 V

+2

V

dB

V

mA

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Document Number: 70014

S-20883—Rev. G, 24-Jun-02

Si9961

Vishay Siliconix

SPECIFICATIONS

T est Conditions

T est Conditions

Unless Otherwise Specified

Unless Otherwise Specified

V+ = 12 V "10%, VDD = 11.6 V "10%

V+ = 12 V "10%, VDD = 11.6 V "10%

V

V

= 5 V "10%, V

= 5 V "10%, V

CC

Parameter UnitMax

Symbol

CC

V

V

REF

REF

= GND = 0 V

= GND = 0 V

REF–

REF–

= 5 V "5%

= 5 V "5%

Min

Supply

I

CC Static, No Load

Supply Current (Standby)

VDD Range V

VCC Range V
V+ Range V+ 10.8 12 13.2

I

V+

I

DD

DD

CC

RETRACT = High 0.2 0.4

ENABLE = High

Normal Mode 10.2 11.6 13.2
Retract Mode 2.0 14

Gain Select Switch

RFB Switch Resistance 108 240
R

Switch Resistance

INH

R

Switch Resistance 810 1800

INL

V

(EXT)

REF

Input Current I
External Voltage Range V

REF

REF

IA2– = 5 V

OA2 = V

REF

Power Supply Monitor

VCC Undervoltage Threshold V
Hysteresis 40 mV
V+ Undervoltage Threshold V
Hysteresis 100 mV

= 5.0 V 3.82 4.12 4.42 V

REF

= 5.0 V 9.1 9.8 10.6 V

REF

Gain Select, RETRACT, ENABLE Input

Input High V oltage V
Input Low Voltage V
Input High Current I
Input Low Current I

IH

IL
IH
IL

VIN = 5 V –1 1
VIN = 0 V –1 1

FAULT Output

Output High Voltage V
Output Low Voltage V

Output High Sourcing Current I

OH

OL

OHS

IOH = –100 A

IOL = 1.6 mA 0.25 0.50

V

= 0 V 400 1100 A

OUT

RETRACT Current Control (RETRACT = Low, Output Current from A to B)

I

Bias Voltage V(I

RET

Retract Output Pull-Up Voltage V
Retract Output Pull-Down Current I
Maximum Emergency Retract Current I

Retract Current VDD Supply Rejection Ratio VDD = 2 V to 14 V, R
Retract Current Temperature Coefficient VDD = 10 V, R

Notes
a. Typical values are for DESIGN AID ONLY, not guaranteed nor subject to production testing.
b. The algebraic convention whereby the most negative value is a minimum and the most positive a maximum.

) VDD = 10 V, R

RET

OUT A

OUTB

(Max) VDD = 2 V, V

OUTB

VDD = 10 V, V

RET

VDD = 2.5 V to 14 V, I

= 5 V R

OUTB

R

= 0.5 , TA = 25_C

SB

= 0.7 V R

OUTB

RET

RET

= 3.74 k 0.66

= 30 mA VDD –1

OUTA

= 3.74 k

RET

= < 10 , RSB = 0.5 , 40

= 3.74 k 3.0 %/V

RET

= 3.74 k –0.3 %/_C

Limits

C Suffix 0 to 70_C

b

4.5 5 5.5

0.15 0.40 0.65 mA

4.75 5 5.25 V

3.5

V

CC

–0.8

22 30 38

a

Typ

0.8 1.6

135 300

V

CC

–0.33

b

0.01

1.5

mA

V



V

A

V

V

mA

mA

Document Number: 70014
S-20883—Rev. G, 24-Jun-02

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3