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