SY21174AADC - High Efficiency, 500kHz, 4A, 18V Input Synchronous Step Down Regulator


  • low RDS(ON) for Internal Switches (Top/Bottom): 50mΩ/30mΩ
  • 4.5-18V Input Voltage Range
  • 4.0A Output Current Capability
  • 500 kHz Switching Frequency
  • Instant PWM Architecture to Achieve Fast Transient Responses.
  • Internal Softstart Limits the Inrush Current
  • Output Discharge Function
  • Cycle-by-cycle Peak Current Limitation
  • ±1.5% 0.6V Reference
  • Pb Free and Halogen Free
  • TSOT23-6 Package

Typical Application


The SY21174A is a high efficiency 500 kHz synchronous step-down DC-DC converter capable of delivering 4.0A current. The SY21174A operates over a wide input voltage range from 4.5V to 18V and integrates main switch and synchronous switch with very low RDS(ON) to minimize the conduction loss.

Low output voltage ripple and small external inductor and capacitor sizes are achieved with 500 kHz switching frequency. It adopts the instant PWM architecture to achieve fast transient responses for high step down applications.


  • Set Top Box
  • Portable TV
  • Access Point Router
  • DSL Modem
  • LCD TV