This document describes a full-bridge power amplifier with features such as precision current control, ±800mA load current, 1.25V total VSAT at 800mA, controlled velocity head parking, etc. It is intended for demanding servo applications such as head positioning for high-density disk drives.
The Unitrode UC3175B is a full-bridge power amplifier rated for a continuous output current of 0.8 Amperes, intended for demanding servo applications such as head positioning in high-density disk drives. The device includes a precision current sense amplifier that allows for accurate load current control using a single series resistor, operating with a very low output saturation voltage down to 4V supply levels.
Key features include power output stage protection via current limiting and thermal shutdown, a dual-input under-voltage comparator for monitoring independent supply voltages, and a programmable constant voltage head park function. Additional auxiliary functions comprise a POWER OK flag output, a LIMIT input to force drive output extremes, and an INHIBIT input to disable amplifiers and reduce quiescent current. The device is available in PLCC and SOIC surface mount packages.
| Continuous Output Current | 0.8 Amperes |
|---|---|
| Total VSAT at 800mA | 1.25V |
| Operating Supply Voltage Range | 4V to 15V |
| Maximum Junction Temperature | +150°C |
| Unity Gain Bandwidth (A Amplifier) | 2 MHz |
| Thermal Shutdown Temperature | 165 °C |
The device is rated for a continuous output current of 0.8 Amperes.
The power amplifier will operate down to 4V supply levels.
The park circuitry overrides the amplifier inputs to convert the power outputs to a programmable constant voltage source.