8958

VOICE COIL

MOTOR DRIVER

www.allegromicro.com

Term.

Terminal Name

Function

1

LOGIC SUPPLY

2

INHIBIT

An active-high logic input that inhibits the output stages without initiating a park.

3 & 4

Under-voltage detection inputs. If not used, these terminals must be connected

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

Power amplifiers’ ground and thermal heat sink.

8

PARK VOLTAGE

Auxiliary inverting input to power amplifier A.

9

Inverting input to current sense error amplifer.

10

Non-inverting input to power amplifier A.

11

Inverting input to power amplifier A.

12

Power amplifier A output to voice coil motor.

13

Power amplifier B output to voice coil motor.

14

LOAD SUPPLY

15

Inverting input to power amplifier B.

16

Non-inverting input to power amplifier B.

17

Non-inverting input to current sense error amplifer.

18 & 19

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

Output of current sense error amplifier.

TERMINAL FUNCTIONS