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UC3178

Full Bridge Power Amplifier

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Precision Current Control

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±450mA Load Current

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1.2V Typical Total Vsat at

450mA

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Programmable Over-Current

Control

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Range Control for 4:1 Gain

Change

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Compensation Adjust Pin for

Range Bandwidth Control

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Inhibit Input and UVLO

•

3V to 15V Operation

•

12mA Quiescent Supply

Current

The UC3178 full-bridge power amplifier, rated for continuous output current

of 0.45 Amperes, is intended for use in demanding servo applications. This

device includes a precision current sense amplifier that senses load current

with a single resistor in series with the load. The UC3178 is optimized to con-

sume a minimum of supply current, and is designed to operate in both 5V

and 12V systems. The power output stages have a low saturation voltage

and are protected with current limiting and thermal shutdown. When inhibited,

the device will draw less than 1.5mA of total supply current.

Auxiliary functions on this device include a load current sensing and rectifica-

tion function that can be configured with the device’s over-current comparator

to provide tight control on the maximum commanded load current. The closed

loop transconductance of the configured power amplifier can be switched be-

tween a high and low range with a single logic input. The 4:1 change in gain

can be used to extend the dynamic range of the servo loop. Bandwidth vari-

ations that would otherwise result with the gain change can be controlled with

a compensation adjust pin.

This device is packaged a power PLCC, "QP" package which maintains a

standard 28-pin outline, but with 7 pins along one edge directly tied to the die

substrate for improved thermal performance.

FEATURES

BLOCK DIAGRAM

DESCRIPTION

UDG-92010