Wide Vin 4.5-28V, 7A, COT Synchronous Step-Down Converter with Internal Bias Supply, Ultra-Sonic Mode at Light Load

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Product Description

The NB638 is a fully integrated, high frequency synchronous rectified step-down switch mode converter. It offers a very compact solution to achieve 7A continuous output current over a wide input supply range with excellent load and line regulation. The NB638 operates at high efficiency over a wide output current load range. Constant-On-Time (COT) control mode provides fast transient response and eases loop stabilization. Full protection features include SCP, OCP, OVP, UVP and thermal shutdown. The NB638 requires a minimum number of readily available standard external components and is available in a space-saving 3mm x 4mm 20-pin QFN package.


Product Features

  • Wide 4.5V to 28V Operating Input Range
  • 7A Output Current
  • Internal 30mO High-Side, 12mO Low-Side Power MOSFETs
  • Proprietary Switching Loss Reduction Technique
  • 1% Reference Voltage
  • Programmable Soft Start Time
  • Soft Shutdown
  • 200kHz to 1MHz Switching Frequency
  • SCP, OCP, OVP, UVP Protection and Thermal Shutdown
  • Output Adjustable from 0.8V to 13V
  • Available in a 20-Pin 3x4mm QFN Package


  • fsw (max) (kHz)1000
  • Vin (min) (V)4.5
  • Vin (max) (V)28
  • Iout (max) (A)7
  • Isw Limit (typ) (A)12
  • Vfb (V)0.815
  • Iq (typ) (mA)0.5
  • Regulated Outputs1
  • Vout (max) (V)13
  • Vout (min) (V)0.815
  • GradeCatalog
  • PackageQFN-20 (3x4)
  • Control ModeCOT
  • Common FeaturesExternal Soft Start, Light-Load Efficiency, Power Good, Synchronous Rectification
  • Special FeaturesProgrammable Frequency, Soft Stop
Quality Policy, Certificates & Reliability Reports
All MPS parts are lead-free, halogen-free and adhere to the RoHS directive. See Environmental section for details.