• Low R_DS(ON) for Internal Switches (Top/Bottom):25mΩ/12mΩ
• 4~40V Input Voltage Range
• 8.0A Output Current Capability
• Selectable 350 kHz/500kHz Switching Frequency
• PFM/PWM Selectable Light Load Operation Mode
• Instant PWM Architecture to Achieve Fast Transient Responses.
• Programmable Soft-start Limits the Inrush Current
• Programmable Valley Current Limit Threshold
• Hic-cup Mode Output Short Circuit Protection
• Power Good Indicator
• 0.6V±1% Reference Voltage
• Compact Package: QFN3.5×3.5-20

The SY21245 high efficiency synchronous Buck
converter can deliver 8A output current over a wide input voltage range from 4V to 40V. The SY21245 employs a constant on-time and ripple-based control strategy to achieve fast transient responses. The SY21245 integrates the top MOSFET and bottom MOSFET with very low R_DS(ON) to minimize the conduction loss.

Silergy’s constant on-time (COT) ripple-based control
method supports high input/output voltage ratios (low duty cycles), and fast transient response while maintaining a near constant operating frequency over line, load, and output voltage ranges. This control method provides stable operation without complex compensation and even with low ESR ceramic capacitors.

The SY21245 also provides input under voltage lockout, cycle-by-cycle current limit, over temperature protection, over voltage protection and output short circuit protection. The SY21245 is available in a compact QFN3.5×3.5-20 package