• Low R_DS(ON) for Internal Switches (Top/Bottom): 55mΩ/36mΩ
• 4.2-18V Input Voltage Range
• 4A Output Current Capability
• 500kHz Switching Frequency Minimize the External Components
• Stable with 22µF C_OUT and 0.68µH Inductor
• Instant PWM Architecture to Achieve Fast Transient Responses
• Internal Soft-Start Limits the Inrush Current
• Cycle-by-cycle Peak/Valley Current Limitation
• Hic-cup Mode Output Short Circuit Protection
• Thermal Shutdown with Auto Recovery
• Output Auto Discharge Function
• Compact Package: TSOT23-6

The SY21174I high-efficiency 500kHz synchronous step-down DC/DC regulator operates over a wide input voltage range of 4.2V to 18V, and can deliver an output current up to 4A. It integrates a top FET and a bottom FET with very low R_DS(ON) to minimize conduction loss. The 500kHz pseudo-constant switching frequency enables using small external inductor and capacitor values.

The SY21174I employs constant on-time and ripple-based control strategy to achieve fast transient response for applications with high step-down ratios, and high efficiency at light loads. It also provides cycle-by-cycle current limiting and over temperature protection.

The SY21174I is highly integrated, so only the input and output capacitors, inductor, and feedback resistors need to be selected for the targeted application specifications.

The SY21174I is available in a compact TSOT23-6 package.