Part Number: UC2843A


Manufacturer: Motorola


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UC2843A image

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Order this document by UC3842A/D UC3842A, 43A UC2842A, 43A High Performance Current Mode Controllers The UC3842A, UC3843A series of high performance fixed frequency current mode controllers are specifically designed for off–line and dc–to–dc converter applications offering the designer a cost effective solution with minimal external components. These integrated circuits feature a trimmed oscillator for precise duty cycle control, a temperature compensated reference, high gain error amplifier, current sensing comparator, and a high current totem pole output ideally suited for driving a power MOSFET. Also included are protective features consisting of input and reference undervoltage lockouts each with hysteresis, cycle–by–cycle current limiting, programmable output deadtime, and a latch for single pulse metering. These devices are available in an 8–pin dual–in–line plastic package as well as the 14–pin plastic surface mount (SO–14). The SO–14 package has separate power and ground pins for the totem pole output stage. The UCX842A has UYLO thresholds of 16 V (on) and 10 V (off), ideally suited for off–line converters. The UCX843A is tailored for lower voltage applications having UVLO thresholds of 8.5 V (on) and 7.6 V (off). • Trimmed Oscillator Discharge Current for Precise Duty Cycle Control HIGH PERFORMANCE CURRENT MODE CONTROLLERS N SUFFIX PLASTIC PACKAGE CASE 626 8 1 D SUFFIX PLASTIC PACKAGE CASE 751A (SO–14) 14 1 • • • • • • • • Current Mode Operation to 500 kHz Automatic Feed Forward Compensation Latching PWM for Cycle–By–Cycle Current Limiting Internally Trimmed Reference with Undervoltage Lockout High Current Totem Pole Output Undervoltage Lockout with Hysteresis Low Startup and Operating Current Direct Interface with Motorola SENSEFET Products PIN CONNECTIONS Compensation 1 Voltage Feedback 2 Current Sense 3 RT/CT 4 (Top View) 8 7 6 5 Vref VCC Output Gnd Compensation NC Voltage Feedback NC Current Sense 1 2 3 4 5 6 7 (Top View) 14 Vref 13 NC 12 VCC 11 VC 10 Output 9 8 Gnd Power Ground Simplified Block Diagram VCC Vref 8(14) R R RTCT 4(7) Voltage Feedback Input 2(3) Output Compensation 1(1) + – NC RT/CT 7(12) 5.0V Reference Vref Undervoltage Lockout Oscillator Latching PWM Error Amplifier VCC Undervoltage Lockout VC 7(11) Output 6(10) Power Ground 5(8) Current Sense 3(5) Input ORDERING INFORMATION Device UC3842AD UC3843AD UC3842AN UC3843AN UC2842AD UC2843AD UC2842AN UC2843AN © Motorola, Inc. 1996 Operating Temperature Range Package SO–14 TA = 0° to +70°C SO–14 Plastic Plastic SO–14 Gnd 5(9) TA = – 25° to +85°C SO–14 Plastic Plastic Rev 1 Pin numbers in parenthesis are for the D suffix SO–14 package. MOTOROLA ANALOG IC DEVICE DATA 1 UC3842A, 43A UC2842A, 43A MAXIMUM RATINGS Rating Total Power Supply and Zener Current Output Current, Source or Sink (Note 1) Output Energy (Capacitive Load per Cycle) Current Sense and Voltage Feedback Inputs Error Am […]

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UC2843A Datasheet

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