Features: · Precision Current Control
· ±800mA Load Current
· 1.25V Total VSAT at 800mA
· Controlled Velocity Head Parking
· Precision Dual Supply Monitor with Indicator
· Limit Input to Force Output Extremes
· Inhibit Input and UVLO
· 4V to 15V operationPinout
SpecificationsInput Supply Voltage, (+VIN,+VC). . . . . . . . . . . . . . . . . . .. . . . . . . . . . . 20V
UV Comparator, and Digital Inputs
Maximum forced voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 10V
Maximum forced current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±10mA
C/S Inputs
Maximum forced voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 20V
A and B Amplifier Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +VIN
Open Collector Output Voltages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20V
A and B Output Currents (continuous)
Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Internally Limited
Sink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0A
Parking Drive Output Current
Continuous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150mA
Pulsed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..1A
Output Diode Current (pulsed) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1A
Power OK Output Current(continuous) . . . . . . . . . . . . . . . . . . . . . . . 30mA
Operating Junction Temperature . . . . . . . . . . . . . . . . . -55°C to +150°C
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . -65°C to +150°C
Note 1: Unless otherwise indicated, voltages are referenced to ground and currents are positive into, negative out of, the specified terminals. "Pulsed" is defined as a less than 10% duty cycle pulse with a maximum duration of 500ms.
Note 2: See Unitrode Integrated Circuits databook for information regarding thermal specifications and limitations of packages.
DescriptionThis full-bridge power amplifier is rated for continuous output current of 0.8 Amperes and is intended for use in demanding servo applications such as head positioning for high-density disk drives. The device includes a precision current sense amplifier that provides accurate control of load current. Current is sensed with a single resistor in series with the load. The power amplifier has a very low output saturation voltage and will operate down to 4V supply levels. Power output stage protection includes current limiting and thermal shutdown.
Auxiliary functions on this device include a dual-input under-voltage comparator, 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 programmable 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 supply 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 ount SOIC package.
UC3175B Data Sheet
