Allegro A8983CJT Datasheet

8983

SPINDLE & VOICE-COIL ACTUATION MANAGER/DRIVER

8983

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

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.

amplifier, error amplifier, and programmable retract circuitry.

Data Sheet

26310.10

SPINDLE & VOICE-COIL

ACTUATION MANAGER/DRIVER

The A8983CJT provides for complete spindle and voice coil power

The spindle driver system incorporates a three-phase MOS power

The voice-coil system incorporates a MOS H-bridge driver, sense

The spindle and voice-coil control functions are supplemented by

an ENERGY MANAGER™, which efficiently channels available spindle

Dwg. PP-060

BEMF to protect the heads and the data disk during system power supply failure. Active regeneration of spindle BEMF provides nearly lossless conversion of spindle BEMF into supply voltage to operate the voice coil motor for parking the heads. A dc-to-dc converter provides for full power MOS r addition, the ENERGY MANAGER provides several energy-saving sleep modes and latched fault states for undervoltage and serial port commanded fault.

The A8983CJT is supplied in a 64-lead low-profile quad flatpack for

surface-mount applications.

performance at minimum supply voltages. In

DS(on)

FEATURES

Voice Coil Motor Driver:

■ Low r

ABSOLUTE MAXIMUM RATINGS

at T

= +25°C

Load Supply Voltage, V Spindle Output Current, I

DISCONTINUED PRODUCT

Voice-Coil Output Current, I Logic Supply Voltage V

Operating Temperature Range,

......................................0°C to +70°C

Output current rating may be restricted to a value determined by system concerns and factors. These include: system duty cycle and timing, ambient temperature, and use of any heatsinking and/or forced cooling.

— FOR REFERENCE ONLY

............ 7.0 V

CC(PWR)

.......... ±1.6 A

OUT(S)

...... ±0.9 A

OUT(A)

................ 6.0 V

CC(D)

■ 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 r

■ 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

MOS Outputs

DS(on)

MOS Outputs

DS(on)

8983

SPINDLE & VOICE-COIL ACTUATION MANAGER/DRIVER

FUNCTIONAL BLOCK DIAGRAM

SPIN

INPUT

ENERGY MANAGER

CONTROLLED RETRACT

DC-DC CONVERSION

SLEEP MODES

UV FAULT

–

SERVO INPUT

SERIAL DATA IN CLOCK DATA ENABLE

–

SLEW

RATE

CONTROL

BACK-EMF AND

COMMUTATION LOGIC

µC SERIAL INTERFACE

EXTERNAL COMMUTATION

TACH

■ 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

Energy Manager:

■ 3.0 V to 5.5 V Operation

■ DC-to-DC Converter Maintains r

Performance

DS(on)

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

115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000

Dwg. FP-028-1

■ 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