·       Low R_DS(ON) for Internal MOSFETs: 80mΩ Top, 40mΩ Bottom

·       Wide Input Voltage Range: 4.5V ~ 18V

·       Up to 3A Output Current

·       ±1.5% 0.6V Reference

·       Precise EN Threshold

·       PFM Light Load Operation for High Efficiency

·       Internal Soft-Start Limits the Inrush Current

·       Support Smooth Startup with Pre-Biased Output

·       500kHz Switching Frequency Minimizes the External Components

·       Constant On-time and Ripple-Based Control to Achieve Fast Transient Responses

·       Stable with 10µF C_OUT

·       Cycle-by-Cycle Valley and Peak Current Limit Protection

·       Hic-Cup Mode Output Under Voltage Protection

·       Auto-Recovery Mode Over Temperature Protection

·       Input Under Voltage Lockout (UVLO)

·       RoHS-Compliant and Halogen-Free

·       Compact Package: SOT23-6

The SY21158 high efficiency 500kHz synchronous buck converter operates over a wide input voltage range of 4.5V to 18V, and can deliver an output current up to 3A. It integrates a top MOSFET and a bottom MOSFET 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 SY21158 uses 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 limit protection, output under voltage protection and over temperature protection.

Only the input and output capacitors, inductor, feedback resistor divider and feedforward capacitor need to be selected for the targeted application specifications.

The SY21158 is available in a compact SOT23-6 package.

The device is part of a family which shares the same package and pinout. The other parts in the family are: SY21086, 2A output current, and SY21158E 3A output current, FCCM (Forced Continuous Conduction Mode).