LD7000 Datasheet, PDF (1/2 Pages) List of Unclassifed Manufacturers – Spindle/VCM Controller and Pre-driver

LD7000
Spindle/VCM Controller and Pre-driver
DESCRIPTION
The LD7000 Servo and Spindle Predriver, a CMOS
monolithic integrated circuit housed in a 64-lead
TQFP package operates from +5 V and +12 V
supplies. It is designed to drive a voice coil actuator
and a 3-phase, Hall-sensorless motor with external
power MOSFETs. The device is intended for use in
12 V disk drive applications.
The actuator driver includes a saturation detector to
monitor the loop compensation amplifier for
saturation, an uncommitted opamp for input signal
conditioning, a voltage reference to provide a precise
voltage level for internal PWM buffers, and reduced
power dissipation.
The spindle driver includes a µP controlled startup
ramp to replace the imprecise analog ramp, an
external PWM input to allow PWM frequencies
above the audible range, active pullup on the P
driver, adjustable N-channel slew rate, and improved
spindle brake performance.
A precision low voltage monitor circuit is also added
to monitor +5 V and +12 V supplies and to initiate
servo head retracts during voltage faults. All
functions are controlled by an SSI compatible
read/write serial port.
Three DC-DC converter circuits for 2.5V,3.3V,&-3/-
5Vsupplies are also available for digital chips and
MR bias negative supply.
FEATURES
• Small footprint 64 or 48 pin TQFP package
• Spindle driver is PWM during run and start
• Commutator is driven by a phase lock loop for
high jitter immunity
• Adjustable slew rate to minimize stress in the
power MOSFETs
• Microprocessor controlled spindle startup
• Saturation detector to monitor loop
compensation amplifier status
• Precision low voltage monitor circuitry for both
+5 V and +12 V supplies, LD7000 only
• Dual level retract scheme includes adjustable
pulse mode, LD7000 only
• Serial Port control
version 2.1