SY21113IADC - High Efficiency, 3.0A, 18V Input Synchronous Step Down Regulator


  • Low RDS(ON) for Internal Switches (Top/Bottom): 80mΩ/40mΩ
  • 4.2-18V Input Voltage Range
  • 3A Output Current Capability
  • 500kHz Switching Frequency Minimize the External Components
  • Stable with 10µF COUT and 2.2µH Inductor
  • Instant PWM Architecture to Achieve Fast Transient Responses
  • Internal Soft-start Limits the Inrush Current
  • Cycle-by-cycle Peak/Valley Current Limitation
  • Hic-cup Mode Output Short Circuit Protection
  • Thermal Shutdown with Auto Recovery
  • Output Auto Discharge Function
  • Compact Package: TSOT23-6

Typical Application


The SY21113I is a high efficiency, 500kHz synchronous step-down DC/DC regulator capable of delivering up to 3A load current. It can operate over a wide input voltage range from 4.2V to 18V and integrate main switch and synchronous switch with very low RDS(ON) to minimize the conduction loss.

The SY21113I 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 500kHz to minimize the size of the inductor and the capacitor.


  • Set Top Box
  • Portable TV
  • DSL Modem
  • LCD TV
  • IP CAM
  • Networking