l Low R_DS(ON) for Internal MOSFETs: 29mΩ Top, 19mΩ Bottom

l Wide Input Voltage Range: 4.5V ~ 18V

l Up to 5A Output Current

l ±1% 0.6V Reference

l Pulse-Frequency Modulation (PFM) Mode Operation

l Internal Soft-Start Limits the Inrush Current

l Support Smooth Startup with Pre-Biased Output

l 400kHz Switching Frequency Minimizes the External Components

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

l Output Auto-Discharge Function

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

l Hic-Cup Mode Output Under Voltage Protection

l Auto-Recovery Mode Over Temperature Protection

l Input Under Voltage Lockout (UVLO)

l RoHS-Compliant and Halogen-Free

l Moisture Sensitivity Level (MSL): 1

l Compact Package: TSOT23-6

The SY81105 high efficiency synchronous buck converter operates over a wide input voltage range of 4.5V to 18V, and can deliver an output current up to 5A. It integrates a top MOSFET and a bottom MOSFET with very low R_DS(ON) to minimize conduction loss. The 400kHz pseudo-constant switching frequency enables using small external inductor and capacitor values.

The SY81105 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 SY81105 is available in a compact TSOT23-6 package.