SY21081C1ABC - High Efficiency, Fast Response, 1.2MHz, 2.0A, 18V Input Synchronous Step Down Regulator


  • Low RDS(ON) for Internal Switches (Top/Bottom): 130mΩ/105mΩ
  • 4.2-18V Input Voltage Range
  • 2A Output Current Capability
  • 1.2MHz Switching Frequency Minimize the External Components
  • Stable with 10µF COUT and 1µH 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
  • Compact Package SOT23-6

Typical Application


The SY21081C1 is a high efficiency, synchronous step-down DC/DC converter capable of delivering 2A load current. The SY21081C1 operates over a wide input voltage range from 4.2V to 18V and integrates main switch and synchronous switch with very low RDS(ON) to minimize the conduction loss.

The SY21081C1 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 1.2MHz to minimize the size of inductor and capacitor.


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