• Suitable for CCM, DCM and QR Mode Flyback Converter
• DRAIN Falling Slope Rate Detecting to Avoid False Turn On of SR MOSFET by Parasitic Ring
• DRAIN High Voltage Blanking Time detecting to enhance system ESD performance
• Dual Power Supply Channel for 3.3V to 12V Output Systems
• Compact Package: SO8

The SY23421 is a synchronous rectification switcher with high performance capabilities, ideal for use in flyback converters operating in CCM (Continuous Conduction), DCM (Discontinuous Conduction), and QR (Quasi-Resonant) modes.

To prevent false turn-on by parasitic ringing under DCM or QR mode, the device uses the DRAIN voltage falling slope rate detection.

The SY23421 features a DRAIN high-voltage blanking time detection function that enhances system ESD performance, preventing external noise from false turn-on of the SR (Synchronous Rectifier) MOSFET.

Under CCM operating mode, it has an extremely short turn-off delay time, while the DRAIN voltage regulation fully utilizes the conduction time of the SR MOSFET for optimizing the efficiency under DCM and QR modes.

During light load conditions, the device enters power saving mode to improve light load efficiency.