8A, 25V, 600kHz Synchronous Step-Down Converter with Integrated LDO



The NB621 is a high frequency synchronous rectified step-down switch mode converter with a built in internal high side power MOSFET and integrated LDO. It offers a very compact solution to achieve 8A continuous output current over a wide input, load and line range. Current mode operation provides fast transient response and eases loop stabilization. Full protection features include OCP and thermal shut down. The NB621 requires a minimum number of readily available standard external components and is available in a space saving 4mm x 5mm 28-pin QFN package.



  • Wide 5.5V to 25V Operating Input Range
  • 8A Output Current
  • Internal Low RDSON Power MOSFETs
  • Fixed 600kHz switching frequency
  • Sync from 300kHz to 2MHz External Clock
  • Integrated 100mA LDO
  • Internal Compensation
  • Power Good Output
  • Integrated Bootstrap Diode
  • OCP Protection and Thermal Shutdown
  • Output Adjustable from 0.8V to 15V
  • Available in 4mm x 5mm 28-pin QFN package.


  • fsw (max) (kHz)600
  • 最小输入电压5.5
  • Vin (max) (V)25
  • Iout (max) (A)8
  • Isw Limit (typ) (A)9.5
  • Max Duty Cycle (%)0.9
  • Vfb (V)0.808
  • Iq (typ) (mA)1.3
  • 额定输出1
  • Vout (max) (V)15
  • Vout (min) (V)0.808
  • GradeCatalog
  • PackageQFN-28 (4x5)
  • Common FeaturesLight-Load Efficiency, Power Good, Synchronous Rectification
  • Special Features外部频率同步