constant torque. This is a very high power dissi-
pation mode, meant only for momentary opera-
tion in unusual circumstances.
Spindown during a power failure uses the back
EMF voltage generated by the spindle motor to
provide power to the VCM amplifier. The Spindle
motor coasts during the Brake Delay time to allow
time to park the head actuator. The park circuit is
a constant voltage circuit settable externally.
After the head is parked, braking commences.
The brake operates by shorting all 3 windings.
The spindle output stages stay on as long as is
VCC = 4.5 to 5.5V
Vdd = 10.8 to 13.2V
0°C < Tamb < 70°C.
required to bring the motor to a complete stop,
even if no power is applied to the part.
A Power On Reset (POR) function provides pulse
stretching for the bidirectional POR\ bus, to en-
sure that the processor and clocks are at running
speed before allowing them to function.
5 volt and 12 volt pins are used directly for the un-
dervoltage detect circuit.
This allows direct use internally of both supplies.
Voltage monitor margining is supported.
An external 3.3V linear regulator is provided and
tied into the POR circuit.
ABSOLUTE MAXIMUM RATINGS
Logic I/O, SH_Out, PWM_DC
All other pins
(1) Limited by chip clamp voltage.
Normal Operating Voltage
Inductive Clamp Voltage @ 2mH, 1.6A, 3% Duty Cycle
Storage Ambient Temperature
-2 to VPWR +2V
-0.3 to VCC +0.3
-0.3 to VPWR +0.3V
-65 to +150
6 5 4 3 2 1 44 43 42 41 40
18 19 20 21 22 23 24 25 26 27 28