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BLOCK DIAGRAM

UC1526A

UC2526A

UC3526A

Regulating Pulse Width Modulator

FEATURES

• Reduced Supply Current

• Oscillator Frequency to 600kHz

• Precision Band-Gap Reference

• 7 to 35V Operation

• Dual 200mA Source/Sink Outputs

• Minimum Output Cross-Conduction

• Double-Pulse Suppression Logic

• Under-Voltage Lockout

• Programmable Soft-Start

• Thermal Shutdown

• TTL/CMOS Compatible Logic Ports

• 5 Volt Operation (V

IN = VC = VREF = 5.0V)

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

connecting V

IN, VC and VREF to a precision 5V input supply. Consult

factory for additional information.

6/93

Summary of content (12 pages)

PAGE 1
UC1526A UC2526A UC3526A Regulating Pulse Width Modulator FEATURES DESCRIPTION • Reduced Supply Current • Oscillator Frequency to 600kHz • Precision Band-Gap Reference • 7 to 35V Operation • Dual 200mA Source/Sink Outputs • Minimum Output Cross-Conduction • Double-Pulse Suppression Logic The UC1526A Series are improved-performance pulse-width modulator circuits intended for direct replacement of equivalent non- “A” versions in all applications.
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UC1526A UC2526A UC3526A ABSOLUTE MAXIMUM RATINGS (Note 1, 2) RECOMMENDED OPERATING CONDITIONS Input Voltage (+VIN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +40V Collector Supply Voltage (+VC) . . . . . . . . . . . . . . . . . . . . . +40V Logic Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +5.5V Analog Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +VIN Source/Sink Load Current (each output) . . . . . . . . . . . .
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UC1526A UC2526A UC3526A ELECTRICAL CHARACTERISTICS: +VIN = 15V, and over operating ambient temperature, unless otherwise specified TA = TJ. UC1526A / UC2526A PARAMETER TEST CONDITIONS UC3526A UNITS MIN TYP MAX MIN TYP MAX 4.95 5.00 5.05 4.90 5.00 5.
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UC1526A UC2526A UC3526A ELECTRICAL CHARACTERISTICS: +VIN = 15V, and over operating ambient temperature, unless otherwise specified TA = TJ. PARAMETER UC1526A UC2526A TEST CONDITIONS MIN UC3526A UNITS TYP MAX 0.1 0.4 50 100 150 ISOURCE = 20mA 12.5 ISOURCE = 100mA 12 MIN TYP MAX 0.1 0.4 V 50 100 150 µA 13.5 12.5 13.5 V 13 12 13 V Soft-Start Section Error Clamp Voltage RESET = +0.4V CS Charging Current RESET = +2.
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UC1526A UC2526A UC3526A APPLICATIONS INFORMATION Voltage Reference The reference regulator of the UC1526A is based on a precision band-gap reference, internally trimmed to ±1% accuracy. The circuitry is fully active at supply voltages above +7V, and provides up to 20mA of load current to external circuitry at +5.0V. In systems where additional current is required, an external PNP transistor can be used to boost the available current.
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UC1526A UC2526A UC3526A APPLICATIONS INFORMATION (cont.) the SYNC pin will then lock the oscillator to the external frequency. capacitor. The logic threshold is +1.1V at +25°C. Noise immunity can be gained at the expense of fan-out with an external 2k pull-up resistor to +5V. Multiple devices can be synchronized together by programming one master unit for the desired frequency, and then sharing its sawtooth and clock waveforms with the slave units.
PAGE 7
UC1526A UC2526A UC3526A APPLICATIONS INFORMATION (cont.) +VC terminal to ground during switching; however, improved design has limited this cross-conduction period to less than 50ns. Capacitor decoupling at VC is recommended and careful grounding of Pin 15 is needed to insure that high peak sink currents from a capacitive load do not cause ground transients. Output Drivers The totem pole output drivers of the UC1526A are designed to source and sink 100mA continuously and 200mA peak.
PAGE 8
UC1526A UC2526A UC3526A TYPICAL CHARACTERISTICS (Cont.) Output Driver Deadtime vs. RD Value Under Voltage Lockout Characteristic Error Amplifier Open Loop Gain vs. Frequency Current Limit Transfer Function Shutdown Delay Output Driver Saturation Voltage UNITRODE INTEGRATED CIRCUITS 7 CONTINENTAL BLVD. • MERRIMACK, NH 03054 TEL.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 10-Jun-2014 (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided.
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IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.