The A8980CJT provides complete drive, management, and control of the voice-coil and spindle motor power actuation subsystems used in hard disk drives. Extensive programmable control features and system diagnostics are provided via a serial interface under the direction of an external microcontroller. The large-scale integration and use of advanced DABiC™ (digital/analog-BiCMOS) merged technologies results in minimum power dissipation, minimum operating voltage requirements, and minimum external components.
The spindle drive function incorporates a three-phase MOS power driver and a back-EMF sensing motor commutation scheme. Internal logic and analog circuitry provide complete start-up and µC-assisted run modes without the need for snubbers or other external components. Additional headroom is achieved by a proprietary circuit, which eliminates the need for an external current-sense resistor. Intrinsic ground clamp and flyback diodes are also provided.

FEATURES
Voice Coil Motor Driver:
■ Low rDS(on) MOS Outputs
■ Lossless Current Sensing
■ Zero Deadband
■ User-Adjustable Transconductance Gain
■ Retract Circuitry Functional to 0 V

Spindle Motor Controller/Driver:
■ Low rDS(on) MOS Outputs
■ Back-EMF Circuitry Eliminates Hall-Effect Sensors
■ Programmable Slew Rate Eliminates Snubbers
■ Lossless Current Sensing
■ Improved Speed Disturbance Performance
■ Dynamic Braking with Delay
■ Active Braking

Servo Compensator/Notch:
■ Over-Velocity Fault Circuitry
■ 12-Bit Servo-Demand DAC
■ Programmable Complex Pole Low-pass-Filter
■ Programmable Notch Frequency, Depth, and Damping

Energy Manager:
■ 3.0 V to 5.5 V Operation
■ Independent Power-Down (Sleep) Modes for all Functional Blocks
■ Efficient Synchronous Rectification Supplies Power During Blackout
■ Thermal Fault Shutdown Circuitry
■ Trimmed Bandgap Voltage Reference
■ Smart DAC Reference Generator
■ Programmable Voltage Reference for Relative Ground
■ Over-Velocity Fault Circuitry
■ Supply Under-Voltage Monitor with Adjustable Trip Point
■ System Diagnostics Data Out
■ Power-On Reset Generator