SY20489BADC - 5.5V Maximum Output, 3A Valley Current, 1MHz Synchronous Boost with Auto Bypass Function


  • 2.5V Minimum Input Voltage
  • Adjustable Output Voltage from 2.5V to 5.5V
  • Min3AValley Current Limit
  • Capable for Seamless Transition between Boost and Bypass Mode
  • Load Disconnect During Shutdown
  • Low RDS(ON) (Main Switch/Synchronous Switch) at 5.0V Output: 50mΩ/90mΩ
  • Output OVP Protection
  • Compact package TSOT23-6

Typical Application


The SY20489B is a high efficiency synchronous, step-up Boost converter designed for one-cell Li-Ion or Li-polymer, or a two to three-cell alkaline Ni-Cd or Ni-MH battery powered applications. It can convert down to 2.5V input voltage and up to 5.5V output voltage. It adopts NMOS for the main switch and PMOS for the synchronous switch.

The SY20489B can disconnect the output from input during the shutdown mode. When input voltage exceeds the regulated output voltage, SY20489B enters bypass mode automatically.


  • All Single Cell Li or Dual Cell Battery Operated Products as MP-3 Player, PDAs, and Other Portable Equipment.