UC3843P

UC3843 Fixed Frequency Current Mode PWM Controller DESCRIPTION UC3843 is a fixed frequency current-mode PWM controller. It is specially designed for Off Line and DC-to-DC converter applications with minimal external component. This integrated circuit features a trimmed oscillator for precise duty cycle control, a temperature compensated reference, a high gain error amplifier, a current sensing comparator, and a high current totem pole output ideally suited for driving a power MOSFET. The device is protective features consisting of input and reference under-voltage lockouts each with hysteresis, cycle-by-cycle current limiting. PIN CONFIGURATION Compensation Voltage Feedback Current Sense RT/CT 1 2 3 4 8 7 6 5 Vref VCC Output GND (Top View) FEATURES ● ● ● ● ● ● ● ● Automatic Feed Forward Compensation High Current Totem Pole Output Internally Trimmed Bandgap Reference Undervoltage Lockout with Hysteresis Low Start Up Current Optimized for offline converter Double pulse suppression Current mode operation to 500kHz APPLICATION ● Wireless Base Station Power ● Telecom and Datacom Power ● Industrial Power Systems ● PC Power Supplies ORDERING INFORMATION Temperature Range 0°C to +70°C Package DIP8L SOP8L Pb-Free Orderable Device UC3843D UC3843P Package Qty 75Units/Tube 50Units/Tube Jun. 2008 Rev 1.0 1 UC3843 SCHEMATIC DIAGRAM VCC 7(12) VCC Undervoltage Lockout VC 7(11) Output Latching PWM + - Vref 8(14) R R RTCT 4(7) Voltage Feedback Input 2(3) Output Compensation 1(1) 5.0V...