The A8983CJT provides for complete spindle and voice coil power electronics for small form-factor HDDs (hard disk drives). The large scale integration and use of advanced DABiC (digital/analog-BiCMOS) merged technologies result in minimum power dissipation, minimum operating voltage, and minimum external components.

The spindle driver system incorporates a three-phase MOS power driver and a back-EMF sensing motor commutation scheme. A patented circuit eliminates the need for an external current-sense resistor, achieving additional headroom. Intrinsic ground clamp and flyback diodes are also provided.

The voice-coil system incorporates a MOS H-bridge driver, sense amplifier, error amplifier, and programmable retract circuitry.

The A8983CJT is supplied in a 64-lead low-profile quad flatpack for surface-mount applications.

FEATURES

Voice Coil Motor Driver:

■ Low rDS(on) MOS Outputs

■ Zero Deadband

■ Externally Determined Transconductance, with Hi/Lo Configuration Switched via Serial Port

■ Current Sensing with External Series Sense Resistor

■ Serial Port Programmable Actuator Retract Circuitry

■ Retract Circuitry Functional to 1.7 V Spindle BEMF

Spindle Motor Controller/Driver:

■ Low rDS(on) MOS Outputs

■ Back-EMF Circuitry Eliminates Hall-Effect Sensors

■ Adaptive Commutation Delay Programmable via Serial Port

■ Programmable Slew Rate (soft switching) Eliminates Snubbers

■ Intrinsic Ground Clamp and Flyback Diodes

■ Patented Lossless Current Sensing Eliminates Need for External Current-Sense Resistor

■ Externally Determined Transconductance, with Hi/Lo Configuration Switched via Serial Port

■ Forward or Reverse Torque Serial Port Bit Allows Improved Speed Disturbance Performance

■ Dynamic Braking with User Delay, Activated by Undervoltage or Serial Port Command

■ Power-On-Reset Generator for Power Up or Power Loss with User-Defined Delay

■ Chip Powers Up in Sleep Mode for Minimum Power Dissipation

■ External 2 MHz System Clock, or Internal Serial Port Trimmed 2 MHz Clock

■ System Diagnostics

■ Uncommitted Op-amp

Energy Manager:

■ 3.0 V to 5.5 V Operation

■ DC-to-DC Converter Maintains rDS(on) Performance at Low Supply

■ Independent Power-Down (Sleep) Modes for all Functional Blocks

■ Efficient Active Regeneration Supplies Power During Retract

■ Supply Under-Voltage Fault Monitor with Adjustable Trip Point