鈥?/div>
Precision Current Control
DESCRIPTION
This full-bridge power amplifier is rated for continuous output current of 0.8 Am-
peres and is intended for use in demanding servo applications such as head
鹵
800mA Load Current
positioning for high-density disk drives. The device includes a precision current
sense amplifier that provides accurate control of load current. Current is
1.25V Total V
SAT
at 800mA
sensed with a single resistor in series with the load. The power amplifier has a
Controlled Velocity Head Parking
very low output saturation voltage and will operate down to 4V supply levels.
Power output stage protection includes current limiting and thermal shutdown.
Precision Dual Supply Monitor
with Indicator
Auxiliary functions on this device include a dual-input under-voltage compara-
Limit Input to Force Output
Extremes
Inhibit Input and UVLO
4V to 15V operation
tor, which can monitor two independent supply voltages and force a built-in
head park function when either is below minimum. When activated by either the
UV comparator, or a command at the separate PARK input, the park circuitry
will override the amplifier inputs to convert the power outputs to a programma-
ble constant voltage source which will hold regulation as the supply voltage
falls to below 3.0 Volts. Added features include a POWER OK flag output, a
LIMIT input to force the drive output to its maximum level in either polarity, and
a over-riding INHIBIT input to disable all amplifiers and reduce quiescent sup-
ply current.
This device is packaged in a power PLCC surface mount configuration which
maintains a standard 28-pin outline, but with 7 pins along one edge allocated to
ground for optimum thermal transfer. And is also available in a 24-pin surface
mount SOIC package.
BLOCK DIAGRAM
Note: Pin numbers refer to PLCC package.
UDG-92054-1
10/94
Powered by ICminer.com Electronic-Library Service CopyRight 2003
1
2
3
4
5
6
