CS51021A, CS51022A, CS51023A, CS51024AEnhanced Current Mode PWM ControllerThe CS51021A/2A/3A/4A Fixed Frequency PWM Current ModeController family provides all necessary features required for AC−DCor DC−DC primary side control. Several features are includedeliminating the additional components needed to implement themexternally. In addition to low startup current (75 A) and highfrequency operation capability, the CS51021A/2A/3A/4A familyincludes overvoltage and undervoltage monitoring, externallyprogrammable dual threshold overcurrent protection, current senseleading edge blanking, current slope compensation, accurate duty cyclecontrol and an externally available 5.0 V reference. The CS51021Aand CS51023A feature bidirectional synchronization capability, whilethe CS51022A and CS51024A offer a sleep mode with 100 Amaximum IC current consumption. The CS51021A/2A/3A/4A familyis available in a 16 lead narrow body SOIC package.Features• 75 A Max. Startup Current• Fixed Frequency Current Mode Control• 1.0 MHz Switching Frequency• Undervoltage Protection Monitor• Overvoltage Protection Monitor with Programmable Hysteresis• Programmable Dual Threshold Overcurrent Protection withDelayed Restart• Programmable Soft Start• Accurate Maximum Duty Cycle Limit• Programmable Slope Compensation• Leading Edge Current Sense Blanking• 1.0 A Sink/Source Gate Drive• Bidirectional Synchronization (CS51021A/3A)• 50 ns PWM Propagation Delay• 100 A Max Sleep Current (CS51022A/4A)• Pb−Free Packages are Available*