L6246

12V VOICE COIL MOTOR DRIVER

12V (

±10%) OPERATION

3A MAXIMUM CURRENT CAPABILITY

0.3

Ω MAXIMUM ON RESISTANCE OF EACH

POWER DMOS AT

A JUNCTION

TEM-

PERATAURE OF 25

°C

CLASS AB POWER AMPLIFIERS

LOGIC AND POWER SUPPLY MONITOR

POWER ON RESET

PARKING FUNCTION WITH SELECTABLE

RETRACT VOLTAGE AND DYNAMIC BRAKE

BEFORE PARKING

ENABLE FUNCTION

GATE DRIVER FOR EXTERNAL BLOCKING

N-MOSFET

OVERTEMPERATURE PROTECTION

OVERTEMPERATURE WARNING OUTPUT

PQFP44 PACKAGE

DESCRIPTION

The voice coil driver L6246 is a linear power am-

plifier designed to drive single phase bipolar DC

motors for hard disk drive applications. The de-

vice contains a selectable transconductance loop,

which allows high precision for head positioning.

The power stage is composed of 2 power amplifi-

ers, in AB class, with 4 DMOSs, with Rdson of

0.5

Ω (Sink+Source) maximum, in a H-bridge con-

figuration. Drive voltage for the upper DMOS

FETs is provided by a charge pump circuit to en-

sure low Rdson.

Automatic brake and parking of the head actuator

is performed by logic or when a failure condition

is detected by power supply monitors. An external

resistor programs the parking voltage that en-

ables the head retract. In addition, a 5V stable

output is provided for the external usage, and a

gate driver circuit enables an external power sup-

ply isolation N-MOSFET.

This device is built in BCD II technology allowing

dense digital circuitry to be combined with high

power bipolar power devices and is assembled in

PQFP44.

February 1998

PQFP44 (10x10)

MULTIPOWER BCD TECHNOLOGY

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