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UC1526

UC2526

UC3526

DESCRIPTION

The UC1526 is a high performance monolithic pulse width modulator

circuit designed for fixed-frequency switching regulators and other

power control applications. Included in an 18-pin dual-in-line pack-

age are a temperature compensated voltage reference, sawtooth os-

cillator, error amplifier, pulse width modulator, pulse metering and

setting logic, and two low impedance power drivers. Also included

are protective features such as soft-start and under-voltage lockout,

digital current limiting, double pulse inhibit, a data latch for single

pulse metering, adjustable deadtime, and provision for symmetry cor-

rection inputs. For ease of interface, all digital control ports are TTL

and B-series CMOS compatible. Active LOW logic design allows

wired-OR connections for maximum flexibility. This versatile device

can be used to implement single-ended or push-pull switching regu-

lators of either polarity, both transformerless and transformer cou-

pled. The UC1526 is characterized for operation over the full military

temperature range of -55°C to +125°C. The UC2526 is characterized

for operation from -25°C to +85°C, and the UC3526 is characterized

for operation from 0° to +70°C.

Regulating Pulse Width Modulator

FEATURES

• 8 To 35V Operation

• 5V Reference Trimmed To ±1%

• 1Hz To 400kHz Oscillator Range

• Dual 100mA Source/Sink Outputs

• Digital Current Limiting

• Double Pulse Suppression

• Programmable Deadtime

• Under-Voltage Lockout

• Single Pulse Metering

• Programmable Soft-Start

• Wide Current Limit Common Mode Range

• TTL/CMOS Compatible Logic Ports

• Symmetry Correction Capability

• Guaranteed 6 Unit Synchronization

BLOCK DIAGRAM

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Summary of content (11 pages)

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UC1526 UC2526 UC3526 Regulating Pulse Width Modulator FEATURES DESCRIPTION • 8 To 35V Operation • 5V Reference Trimmed To ±1% • 1Hz To 400kHz Oscillator Range • Dual 100mA Source/Sink Outputs • Digital Current Limiting • Double Pulse Suppression • Programmable Deadtime • Under-Voltage Lockout • Single Pulse Metering • Programmable Soft-Start • Wide Current Limit Common Mode Range • TTL/CMOS Compatible Logic Ports The UC1526 is a high performance monolithic pulse width modulator ci
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UC1526 UC2526 UC3526 ABSOLUTE MAXIMUM RATINGS (Note 1, 2) RECOMMENDED OPERATING CONDITIONS (Note 3) 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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UC1526 UC2526 UC3526 ELECTRICAL CHARACTERISTICS: +VIN = 15V, and over operating ambient temperature, unless otherwise specified, TA = TJ. PARAMETER TEST CONDITIONS UC1526 / UC2526 MIN TYP MAX UC3526 MIN UNITS TYP MAX Oscillator Section (Note 5) Initial Accuracy TJ = + 25°C ±3 ±8 ±3 ±8 % Voltage Stability +VIN = 8 to 35V 0.5 1 0.5 1 % Temperature Stability Over Operating TJ 7 10 3 Minimum Frequency RT = 150kΩ Ω, CT = 20µ µF Maximum Frequency RT = 2kΩ Ω, CT = 1.
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UC1526 UC2526 UC3526 APPLICATIONS INFORMATION Voltage Reference The reference regulator of the UC1526 is based on a temperature compensated zener diode. The circuitry is fully active at supply voltages above +8V, 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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UC1526 UC2526 UC3526 APPLICATIONS INFORMATION (cont.) TTL, open-drain CMOS, and open-collector voltage comparators; fan-in is equivalent to 1 low-power Schottky gate. Each port is normally HIGH; the pin_____ is pulled LOW _ to activate the particular function. Driving SYNC LOW initiates a discharge cycle in the oscillator. Pulling ____________ SHUTDOWN LOW immediately inhibits all PWM output _______ pulses. Holding RESET LOW discharges the soft-start capacitor. The logic threshold is +1.1V at +25°C.
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UC1526 UC2526 UC3526 Figure 6. Error Amplifier Connections Figure 8. Single-Ended Configuration Figure 7. Push-Pull Configuration Figure 9.
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UC1526 UC2526 UC3526 TYPICAL CHARACTERISTICS 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.com 31-May-2014 NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.
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PACKAGE OPTION ADDENDUM www.ti.
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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.