• Low R_DS(ON) for Internal Switches (Top/Bottom): 350mΩ/150mΩ
• 4.5V-28V Input Voltage Range
• 1.7A Output Current Capability
• 500kHz Switching Frequency Minimizes the External Components
• Instant PWM Architecture to Achieve Fast Transient Responses
• Internal Soft-start Limits the Inrush Current
• Cycle-by-cycle Valley Current Limitation
• ±2.0% 0.6V Reference
• RoHS Compliant and Halogen Free
• Compact Package: TSOT23-6

The SY21042 develops high efficiency 500kHz synchronous step-down DC/DC converter capable of delivering 1.7A current. The device operates over a wide input voltage range from 4.5V to 28V and integrates main switch and synchronous switch with very low R_DS(ON) to minimize the conduction loss.

The SY21042 adopts the instant PWM architecture to achieve fast transient responses for high step down applications and high efficiency at light loads. In addition, it operates at pseudo-constant frequency of 500 kHz under heavy load conditions to minimize the size of inductor and capacitor.