8983 Datasheet, PDF (1/2 Pages) Allegro MicroSystems – SPINDLE & VOICE-COIL ACTUATION MANAGER/DRIVER

8983
8983 ^{SPINDLE & VOICE-COIL}
ACTUATION MANAGER/DRIVER
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.
RODUOCNTLY _{Dwg. PP-060}
CONTIRNEUFEEDRPENCE ABSOLUTE MAXIMUM RATINGS
at T_A = +25°C
IS ^{R Load Supply Voltage, V}
............ 7.0 V
CC(PWR)
Spindle Output
Current, I
OUT(S)
..........
±1.6
A
D O Voice-Coil Output Current, I ......
OUT(A)
±0.9
A
F Logic Supply Voltage V ................ 6.0 V
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 r_DS(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.
The A8983CJT is supplied in a 64-lead low-profile quad flatpack for
surface-mount applications.
FEATURES
Voice Coil Motor Driver:
s Low r_DS(on) MOS Outputs
s Zero Deadband
s Externally Determined Transconductance, with Hi/Lo
Configuration Switched via Serial Port
s Current Sensing with External Series Sense Resistor
s Serial Port Programmable Actuator Retract Circuitry
s Retract Circuitry Functional to 1.7 V Spindle BEMF
—^CC(D)
Operating Temperature Range,
T_A ...................................... 0°C to +70°C
Output current rating may be restricted to a value
Spindle Motor Controller/Driver:
s Low r_DS(on) MOS Outputs
s Back-EMF Circuitry Eliminates Hall-Effect Sensors
determined by system concerns and factors.
s Adaptive Commutation Delay Programmable via Serial Port
These include: system duty cycle and timing,
ambient temperature, and use of any heatsinking
and/or forced cooling.
s Programmable Slew Rate (soft switching) Eliminates Snubbers
s Intrinsic Ground Clamp and Flyback Diodes