General Description

The SY21173 high-efficiency asynchronous Buck

converter can deliver 3A output current over a

wide input voltage range from 4.5V to 60V. The

SY21173 employs a constant off-time and peakcurrent mode control strategy to achieve fast

transient responses. It integrates a main switch

with low RDS(ON) to minimize conduction loss.

The adjustable switching frequency permits low

output-voltage ripple and reduces external

inductor and capacitor sizes. The SY21173 also

provides cycle-by-cycle current limiting, over

temperature protection, and output short circuit

protection.

The SY21173 is available in a compact SO8E

package.

Features

● Low RDS(ON) for Internal N-Channel Power

FET: 150mΩ

● 4.5V to 60V Input Voltage Range

● Up to 3A Output Current Capability

● Constant Off-Time and Peak-Current

Mode Control

● Internal Soft-Start Limits the Inrush

Current

● ±1% 0.8V Reference

● Adjustable Switching Frequency Range:

100kHz to 1MHz

● EN ON/OFF Control with Accurate

Threshold

● Hiccup Mode Output Short Circuit

Protection

● Cycle-by-Cycle Peak Current Limit

● RoHS-Compliant and Halogen-Free

● Compact Package: SO8E

Applications

● Non-Isolated Telecommunication Buck

Regulator

● Secondary High-Voltage Post Regulator

● Automotive Systems

● Electric Bicycle