BLOCK DIAGRAM

UC1526A

UC2526A

UC3526A

Regulating Pulse Width Modulator

FEATURES

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Reduced Supply Current

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Oscillator Frequency to 600kHz

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Precision Band-Gap Reference

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7 to 35V Operation

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Dual 200mA Source/Sink Outputs

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Minimum Output Cross-Conduction

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Double-Pulse Suppression Logic

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Under-Voltage Lockout

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Programmable Soft-Start

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Thermal Shutdown

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TTL/CMOS Compatible Logic Ports

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DESCRIPTION

The UC1526A Series are improved-performance pulse-width modu-

lator circuits intended for direct replacement of equivalent non- “A”

versions in all applications. Higher frequency operation has been

enhanced by several significant improvements including: a more ac-

curate oscillator with less minimum dead time, reduced circuit de-

lays (particularly in current limiting), and an improved output stage

with negligible cross-conduction current. Additional improvements

include the incorporation of a precision, band-gap reference gener-

ator, reduced overall supply current, and the addition of thermal

shutdown protection.

Along with these improvements, the UC1526A Series retains the

protective features of under-voltage lockout, soft-start, digital cur-

rent limiting, double pulse suppression logic, and adjustable

deadtime. For ease of interfacing, all digital control ports are TTL

compatible with active low logic.

Five volt (5V) operation is possible for “logic level” applications by

factory for additional information.

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