The A8902CLBA is a three-phase brushless dc motor controller/ driver for use in 5 V or 12 V hard-disk drives. The three half-bridge outputs are low on-resistance n-channel DMOS devices capable of driving up to 1.25 A. The A8902CLBA provides complete, reliable, self-contained back-EMF sensing motor startup and running algorithms. A programmable digital frequency-locked loop speed control circuit together with the linear current control circuitry provides precise motor speed regulation.

FEATURES

■ DMOS Outputs

■ Low rDS(on)

■ Startup Commutation Circuitry

■ Back-EMF Commutation Circuitry

■ Serial Port Interface

■ Frequency-Locked Loop Speed Control

■ Sector Data Tachometer Signal Input

■ Programmable Start-Up Current

■ Diagnostics Mode

■ Sleep Mode

■ Linear Current Control

■ Internal Current Sensing

■ Dynamic Braking Through Serial Port

■ Power-Down Dynamic Braking

■ System Diagnostics Data Out

■ Data Out Ported in Real Time

■ Internal Thermal Shutdown Circuitry