driver and a back-EMF sensing motor commutation scheme. A pat-
achieving additional headroom. Intrinsic ground clamp and flyback
diodes are also provided.
amplifier, error amplifier, and programmable retract circuitry.
Dwg. PP-060
鈩?/div>
, 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 E
NERGY
M
ANAGER
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
Spindle Motor Controller/Driver:
s
Low r
DS(on)
MOS Outputs
s
Back-EMF Circuitry Eliminates Hall-Effect Sensors
s
Adaptive Commutation Delay Programmable via Serial Port
s
Programmable Slew Rate (soft switching) Eliminates Snubbers
s
Intrinsic Ground Clamp and Flyback Diodes
1
2
