21V, 3A, 500kHz Synchronous Step-down Converter

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Product Description

The MP28256 is a synchronous rectified step-down switch mode converter with built in internal power MOSFETs. It offers a very compact solution to achieve 3A continuous output current over a wide input supply range with excellent load and line regulation. The MP28256 has synchronous mode operation for higher efficiency over output current load range.  Current mode operation provides fast transient response and eases loop stabilization. Full protection features include OCP and thermal shut down.  The MP28256 requires a minimum number of readily available standard external components and is available in a space saving QFN14 (3x4mm) package.


Product Features

  • Wide 4.5V to 21V Operating Input Range
  • 0.6V internal reference with 2% accuracy
  • 3A Output Current
  • Low Rds(ON) Internal Power MOSFETs
  • Fixed 500kHz Switching Frequency
  • Frequency SYNC from 300kHz to 2MHz External Clock
  • External Soft Start
  • OCP and Thermal Shutdown
  • Separate EN and SYNC pins
  • Available in a QFN14 (3x4mm) Package.


  • fsw (max) (kHz)500
  • Vin (min) (V)4.5
  • Vin (max) (V)21
  • Iout (max) (A)3
  • Isw Limit (typ) (A)4.2
  • Max Duty Cycle (%)0.9
  • Vfb (typ) (V)0.603
  • Iq (typ) (mA)0.7
  • Regulated Outputs1
  • Vout (max) (V)18
  • Vout (min) (V)0.6
  • GradeCatalog
  • PackageQFN-14 (3x4)
  • Common FeaturesExternal Soft Start, Synchronous Rectification
  • Special FeaturesExternal Frequency Sync

Reference Materials