A8983CJT [ALLEGRO]
SPINDLE & VOICE-COIL ACTUATION MANAGER/DRIVER; 主轴和音圈ACTUATION经理/驱动器
| 型号： | A8983CJT |
| 厂家： | 
ALLEGRO MICROSYSTEMS |
| 描述： | SPINDLE & VOICE-COIL ACTUATION MANAGER/DRIVER |
| 文件： | 总2页 (文件大小：42K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
8983
SPINDLE & VOICE-COIL
ACTUATION MANAGER/DRIVER
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 pat-
ented 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 spindle and voice-coil control functions are supplemented by
™
an ENERGY MANAGER , which efficiently channels available spindle
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 rDS(on) performance at minimum supply voltages. In
addition, the ENERGY MANAGER provides several energy-saving sleep
modes and latched fault states for undervoltage and serial port com-
manded fault.
Dwg. PP-060
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
ABSOLUTE MAXIMUM RATINGS
at T = +25°C
A
Load Supply Voltage, VCC(PWR) ............ 7.0 V
Spindle Output Current, IOUT(S) .......... ±1.6 A
Voice-Coil Output Current, IOUT(A) ...... ±0.9 A
Logic Supply Voltage VCC(D) ................ 6.0 V
Operating Temperature Range,
Spindle Motor Controller/Driver:
■ Low rDS(on) MOS Outputs
TA ...................................... 0°C to +70°C
■ 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
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.
8983
SPINDLE & VOICE-COIL
ACTUATION MANAGER/DRIVER
FUNCTIONAL BLOCK DIAGRAM
ENERGY MANAGER
+
CONTROLLED RETRACT
DC-DC CONVERSION
SLEEP MODES
UV FAULT
–
+
SERVO
INPUT
g
m
–
SERIAL DATA IN
CLOCK
+
SPIN
DATA ENABLE
INPUT
–
g
SLEW
RATE
m
CONTROL
EXTERNAL
COMMUTATION
BACK-EMF AND
COMMUTATION LOGIC
TACH
Dwg. FP-028-1
■ Patented Lossless Current Sensing Eliminates Need
for External Current-Sense Resistor
■ Externally Determined Transconductance, with Hi/Lo
Configuration Switched via Serial Port
■ Power-On-Reset Generator for Power Up or
Power Loss with User-Defined Delay
■ Chip Powers Up in Sleep Mode for Minimum
Power Dissipation
■ Forward or Reverse Torque Serial Port Bit Allows
Improved Speed Disturbance Performance
■ Dynamic Braking with User Delay, Activated by
Undervoltage or Serial Port Command
■ 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
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 1995, Allegro MicroSystems, Inc.
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