DESCRIPTION

The L6254 integrates into a single chip both spindle and VCM controllers as well as power stages. The device is designed for 12V disk drive application requiring up to 2.0A of spindle and 1.5A of VCM peak currents.

GENERAL

■ 12V (±10) OPERATION.

■ REGISTER BASED ARCHITECTURE

■ MINIMUM EXTERNAL COMPONENTS

■ BICMOS + VERTICAL DMOS (1.5mm)

VCM DRIVER

■ 1.5A DRIVE CAPABILITY

■ 0.9W TOTAL BRIDGE IMPEDANCE AT 25°C

■ LINEAR MODE

■ PHASE SHIFT MODULATION (PWM MODE)

■ INSTANTANEOUS, (GLICH FREE) SWITCH BETWEEN THE 2 MODES

■ CLASS AB OUTPUT DRIVERS

■ ZERO CROSSOVER DISTORSION

■ 14 BIT DAC DEFINE OUTPUT CURRENT

■ SELECTABLE TRANSCONDUCTANCE

■ 4 PROGRAMMABLE PARKING VOLTAGE

■ DYNAMIC BRAKE

SPINDLE DRIVER

■ 2.0A DRIVE CAPABILITY

■ 0.8W TOTAL BRIDGE IMPEDANCE AT 25°C

■ BEMF, INTERNAL OR EXTERNAL, PROCESSING

■ SENSOR-LESS MOTOR COMMUTATION

■ PROGRAMMABLE COMMUTATION PHASE DELAY

■ LINEAR MODE AND CONSTANT TOFF PWM OPERATION MODE

■ INTERNAL FREQUENCY LOCKED LOOP SPEED CONTROL (FLL)

■ BEMF RECTIFICATION DURING RETRACT

■ BUILT-IN ALIGNAMENT&GO START-UP

■ INDUCTIVE SENSING START UP OPTION

■ RESYNCHRONIZATION

■ DYNAMIC & REVERSE BRAKE

■ CONTROLLABLE OUTPUT SLEW RATE

OTHER FUNCTIONS

■ 12V AND 5V MONITORING WITH EXTERNAL SET TRIP POINTS AND HYSTERESIS

■ POWER UP/DOWN SEQUENCING

■ LOW VOLTAGE SENSE

■ SLUG FOR POWER DISSIPATION

■ THERMAL SHUTDOWN AND PRETHERMAL WARNING