Datasheet A8958CLB Datasheet (Allegro)

LOGIC

SUPPLY

INHIBIT

LIMIT

GROUND

GROUND

PARK

VOLTAGE
SENSE

OUT

UV

UV

AB

AB

IN–

IN

A+

IN

A–

A

V

1

CC

2

1.5 V

3

1

4

2

5

6

7

8

9

9

10

11

12

+

-

+

B

+

A

-

-

V

BB

24

23

22

21

20

19

18

17

16

15

14

13

SENSE

PARK
DRIVE

PARK

GROUND

PWR OK

GROUND

GROUND

SENSE

IN

B+

IN

B–

LOAD
SUPPLY

OUT

Dwg. PP-054

ABSOLUTE MAXIMUM RATINGS

at T

= 25°C

A

Supply Voltages, VBB and VCC...............16 V

Output Current, I
Park Drive Output Current, I

Continuous................................ 250 mA

Peak.............................................. 1.0 A

Amplifier Input Voltage Range,

..................................... -2.0 V to V

V

IN

Sense Input Voltage Range,

V

SENSE IN

Comparator and Digital Inputs,

V

....................................-0.3 V to 10 V

IN

.............................................. ±10 mA

I

IN

Power OK Output, V

I

................................................. 30 mA

C

Output Clamp Diode Current,

(pulsed) ..................................... 1.0 A

I

F

Package Power Dissipation, P
Operating Temperature Range,

......................................0°C to +70°C

T

A

Junction Temperature, T
Storage Temperature Range,

................................ -55°C to +150°C

T

S

* Fault conditions that produce excessive junction
temperature will activate device thermal shutdown
circuitry. These conditions can be tolerated but
should be avoided.

............................±1.0 A

OUT

PARK

............................ -0.3 V to V

.........................20 V

CEX

.. See Graph

D

...................150°C*

J

Data Sheet

26300.5A

8958

VOICE COIL MOTOR DRIVER

Providing control and drive of the voice coil motor used for head

OUT

AB

AB

IN+

B

CC

CC

positioning in disk drive applications, the A8958CLB is a full-bridge
driver which can be configured so that its output current is a direct
function of an externally applied control voltage or current. This linear
current control function is supplemented by additional circuitry to
protect the heads and the data disk during system failure or normal
system shutdown.

The two ±800 mA driver outputs provide very-low saturation voltage
drops and precise current control utilizing a single current-sensing
resistor connected in series with the load. Under-voltage lockout
disables the system in a controlled sequence if a fault condition occurs.

When activated by the under-voltage comparator, or a park com­mand, the output power drivers change from a controlled current to a
user-determined constant park voltage. Other features include a power
ok flag, a limit input to force the outputs to their maximum level in either
polarity, an over-riding output disable to shut down both power amplifi­ers and reduce quiescent supply current, and internal thermal shutdown
which disables the load (but still allowing the head to be parked) in the
event of excessive junction temperatures. The load is re-enabled when
the junction temperature returns to a safe level.

The A8958CLB is supplied in a 24-lead power SOIC for surface­mount applications. The copper batwing construction provides for
maximum package power dissipation in a minimum package size. It is
rated for continuous operation over the temperature range of 0°C to
+70°C.

FEATURES

■ Controlled-Velocity Head Parking

■ Zero Deadband

■ High Transconductance Bandwidth

■ User-Adjustable Transconductance Gain

■ ±800 mA Load Current

■ Dual Under-Voltage Monitors

with Flag and User-Selectable Trip Points

■ Internal Thermal Shutdown Circuitry

■ Replaces UC3175

Always order by complete part number, e.g., A8958CLB .

8958

VOICE COIL
MOTOR DRIVER

PARK

LIMIT

IN

IN

PARK

PWR OK

8

5

1.5 V

11

A–

10

A+

6, 7 18, 19

AB

4 kΩ

17

IN+

9

IN–

4 kΩ

22

20

VOLTAGE

GROUND

SENSE

SENSE

(ACTIVE HIGH)

FUNCTIONAL BLOCK DIAGRAM

LOAD

14

SUPPLY

+
–

–

8 kΩ

1.5 V

+

–

8 kΩ

A

+

SENSE

12

OUT

A

24

OUT

V

BB

–

13

OUT

B

B

+

1.5 V

BANDGAP REF

TSD

V

CC

–
+

3 V

+

–

1.5 V

21

GROUND

+

–

2

15

16

23

1

4

3

INHIBIT

IN

B–

IN

B+

GROUND
PARK

DRIVE

LOGIC
SUPPLY

UV

1

UV

2

AB

5

R = 6.0°C/W

4

θJT

3

2

R = 55°C/W

1

0

25

ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS

θJA

50 75 100 125 150

TEMPERATURE IN °C

Dwg. GP-033A

Dwg. FP-020C

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

Copyright © 1990, 2000 Allegro MicroSystems, Inc.

8958

VOICE COIL

MOTOR DRIVER

ELECTRICAL CHARACTERISTICS at T

= +25°C, V

A

= VBB = 12 V

CC

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Units

Logic Supply Voltage Range V
Logic Supply UV Threshold V
Logic Supply UV Hysteresis ∆V
Supply Current I

CC

CC

CC

BB

I

CC

Inhibited Supply Current — I
Thermal Shutdown Temp. T
Thermal Shutdown Hysteresis ∆T

J

J

Operating 8.0 12 16 V
High-to-low transition — 2.8 3.0 V

— 200 — mV

V

= 6 V, no load — 2.0 — mA

OUT

— 23 — mA

+ ICC, V2 ≥ 1.7 V — 3.0 8.0 mA

BB

— 165 — °C
— 8.0 — °C

Output Power Drivers

Output Saturation Voltage V

Total Saturation Voltage V
(Source + Sink)

Input Offset Voltage V
Input Offset Drift ∆V
Input Bias Current I

Input Offset Current I
Differential Sense Input Current I

Large Signal Gain A

SAT

SAT

IO

IO

IN

IO

ID

VS

I

= 250 mA — 250 — mV

OUT

I

= 800 mA — 450 — mV

OUT

I

= -250 mA — 750 — mV

OUT

I

= -800 mA — 950 — mV

OUT

I

= 250 mA — 1.0 1.4 V

LOAD

I

= 800 mA — 1.4 2.0 V

LOAD

VCM = 6 V — 5.0 8.0 mV

——25 µV/°C
Except INA+, VCM = 6 V — -150 -500 nA
IN

to SENSE

A+

= 12 kΩ, TJ = 25°C 69 84 105 µA/V

IN+

INB only, VCM = 6 V ——200 nA
I

= 5 mA — ±300 — µA

OUT

I

= 500 mA — 3.0 — mA

OUT

V

= 2 V to 10 V, I

OUT

= ±500 mA 1.5 5.0 — V/mV

OUT

Slew Rate SR — 4.0 — V/µs
Unity Gain Bandwidth BW Amplifier A 0.5 1.0 1.7 MHz

Amplifier B 0.5 2.0 2.2 MHz

Common-Mode Rejection k
Clamp Diode Forward Voltage V
High-Side Current Limit I
Power Supply Rejection k

Negative current is defined as coming out of (sourcing) the specified device terminal.
Typical Data is for design information only.

CMR

F

OUT

SVR

VCM = 1 V to 10 V 70 90 — dB
IF = 800 mA, V2 ≥ 1.7 V — 1.0 1.2 V
TJ = 25°C — 1.0 1.2 A
VCC = 4 V to 15 V, VCM = 1.5 V 70 90 — dB

Continued next page...

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8958

VOICE COIL
MOTOR DRIVER

ELECTRICAL CHARACTERISTICS (continued)

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Units
Current Sense Amplifier

Input Offset Voltage V
Input Offset Drift ∆V

Voltage Gain A
Output Saturation Voltage V

Park Function

IO

IO

VS

SAT

VCM = 6 V ——2.0 mV
VCM = 0 V to 12 V ——3000 µV/V

——8.0 µV/°C
VID = -1 V to +1 V, VCM = 6 V 1.95 2.00 2.05 —
V

OUT, IOUT(SINK)

V

- V

CC

OUT

= 1.5 mA — 300 500 mV

, I

OUT(SOURCE)

= -1.5 mA — 400 700 mV

PARK DRIVE Leakage Current I
PARK DRIVE Saturation Voltage V

CE(SAT)

PARK Input Threshold V
PARK Input Current I
PARK VOLTAGE Input Current I

PARK

PARK V

Under-Voltage Protection

UV Threshold V
UV Threshold Hysteresis ∆V
UV Input Current I
PWR OK Saturation Voltage V

CE(SAT)

PWR OK Leakage Current I

Auxiliary Functions

LIMIT Input Voltage V

LIMIT(L)

V

LIMIT(H)

V

LIMIT Input Resistance R
INHIBIT Input Threshold V
INHIBIT Input Current I

CEX

PARK

UV

UV

UV

CEX

LIMIT

LIMIT

2

2

V

= 20 V ——100 µA

CEX

IC = 200 mA — 300 500 mV

0.7 1.1 1.7 V

V

= 1.7 V ——100 µA

PARK

— -150 -500 nA

Low-to-High Trans., Other Input = 6 V 1.48 1.50 1.52 V

15 25 45 mV
VUV = 1 V — -0.5 -1.5 µA
IC = 5 mA ——450 mV
V

= 20 V ——5.0 µA

CEX

OUTA forced Low 0.7 0.8 — V
OUTA forced High — 2.2 2.3 V
Limit inactive 1.2 — 1.8 V
Open circuit 1.45 1.50 1.55 V
V

= 1.2 V to 1.8 V — 10 — kΩ

LIMIT

0.7 1.1 1.7 V

V2 = 1.7 V ——200 µA

Negative current is defined as coming out of (sourcing) the specified device terminal.
Typical Data is for design information only.

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

VOICE COIL

MOTOR DRIVER

TERMINAL FUNCTIONS

Term. Terminal Name Function

1 LOGIC SUPPLY VCC; logic supply voltage.
2 INHIBIT An active-high logic input that inhibits the output stages without initiating a park.

8958

3 & 4 UV

and UV

1

2

Under-voltage detection inputs. If not used, these terminals must be connected
to the logic supply (VCC).

5 LIMIT A tri-state input that forces the output of amplifier A into saturation in either direction,

or allows normal linear operation.

6 & 7 GROUND

AB

Power amplifiers’ ground and thermal heat sink.
8 PARK VOLTAGE Auxiliary inverting input to power amplifier A.
9 SENSE

10 IN
11 IN
12 OUT
13 OUT

IN–

A+

A–

A

B

Inverting input to current sense error amplifer.

Non-inverting input to power amplifier A.

Inverting input to power amplifier A.

Power amplifier A output to voice coil motor.

Power amplifier B output to voice coil motor.

14 LOAD SUPPLY VBB; load supply voltage.
15 IN
16 IN

B–

B+

17 SENSE

18 & 19 GROUND

IN+

AB

Inverting input to power amplifier B.

Non-inverting input to power amplifier B.

Non-inverting input to current sense error amplifer.

Power amplifiers’ ground and thermal heat sink.

20 PWR OK A logic low at this output indicates an under-voltage condition.
21 GROUND Circuit reference.
22 PARK An active-high logic input that activates the park function.
23 PARK DRIVE Power transistor for retract current control on power down or park command.
24 SENSE

OUT

Output of current sense error amplifier.

www.allegromicro.com

8958

VOICE COIL
MOTOR DRIVER

CURRENT SENSING

500 pF 330 kΩ

R

FA

+

V

S

–

IN

A–

–

A

+

IN

A+

R

FB

OUT

A

8 kΩ

I

LOAD

10 kΩ

SENSE

SENSE

4 kΩ

10 kΩ

R

SENSE

OUT

B

SENSE

IN+

–

+

OUT

IN–

4 kΩ

8 kΩ

IN

B–

–

B

+

IN

B+

Dwg. EP-034

PARKING FUNCTION

R

1

IN

R

–

A

+

OUT

A

I

PARK

SENSE

OPTIONAL
PARK CURRENT
LIMIT

PARK
DRIVE

OUT

B

B

B–

–

IN

B+

+

R

2

PARK

VOLTAGE

1.5 V

PARK

PWR OK

(ACTIVE HIGH)

–

+

–

+

+

V

OUT A

1.5 (R1 + R2)

=

R

2

–

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

1.5 V

3 V

V

CC

UV

UV

1

2

Dwg. EP-039

Dimensions in Inches

(for reference only)

8958

VOICE COIL

MOTOR DRIVER

0.2992

0.2914

0.020

0.013

0.0926

0.1043

24 13

1 2

3

0.6141

0.5985

0.0040

MIN

.

Dimensions in Millimeters

(controlling dimensions)

24 13

0.050

BSC

NOTE 1
NOTE 3

0.0125

0.0091

0.491

0.394

0.050

0.016

0° TO 8

Dwg. MA-008-25 in

0.32

0.23

7.60

7.40

1 2

0.51

0.33

3

15.60

15.20

1.27

BSC

NOTE 1
NOTE 3

2.65

2.35

0.10

MIN

.

NOTES: 1. Webbed lead frame. Leads 6, 7, 18, and 19 are internally one piece.

2. Lead spacing tolerance is non-cumulative.

3. Exact body and lead configuration at vendor’s option within limits shown.

www.allegromicro.com

10.65

10.00

1.27

0.40

0° TO 8

Dwg. MA-008-25A mm

8958

VOICE COIL
MOTOR DRIVER

The products described here are manufactured under one or more

U.S. patents or U.S. patents pending.

Allegro MicroSystems, Inc. reserves the right to make, from time to
time, such departures from the detail specifications as may be required
to permit improvements in the performance, reliability, or
manufacturability of its products. Before placing an order, the user is
cautioned to verify that the information being relied upon is current.

Allegro products are not authorized for use as critical components
in life-support devices or systems without express written approval.

The information included herein is believed to be accurate and
reliable. However, Allegro MicroSystems, Inc. assumes no responsi­bility for its use; nor for any infringement of patents or other rights of
third parties which may result from its use.

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]