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Monolithic Power Systems

Monolithic Power Systems MP431x Scalable 2-7A Buck Converters

45V (50 max), 2A to 7A Synchronous Step-down Switching Converter with Low IQ, Configurable Frequency

The MP431x is a 45V (50 max) family of buck converters with low IQ, spread spectrum technology, and current ratings of 2A to 7A with the same QFN20 pinout. It can therefore be used across multiple designs with minimal layout change, making DC/DC one less thing to worry about when taking your next product to market.

The MP431x is a synchronous step-down switching converter with a configurable frequency, as well as an integrated internal high-side MOSFET (HS-FET) and low-side MOSFET (LS-FET). The device provides from 2A to 7A of highly efficient output current (IOUT) with current mode control for fast loop response. The wide 3.3V to 45V input voltage (VIN) range accommodates a variety of step-down applications in automotive input environments. The MP431x’s low 1.7μA shutdown mode and 18uA quiescent current (IQ) makes the device well-suited for battery-powered applications.

High power conversion efficiency across a wide load range is achieved by scaling down the switching frequency (fSW) under light-load conditions to reduce the switching and gate driver losses. An open-drain power good (PG) signal indicates whether the output is within 93% to 106% of its nominal voltage. Frequency foldback helps prevent inductor current runaway during start-up. Thermal shutdown provides reliable, fault-tolerant operation. High duty cycle and low-dropout mode are provided for the automotive cold-crank conditions.

Typical Application

Monolithic Power Systems – MP431x Buck Converter Typical Application


  • Wide 3.3V to 45V Operating Input Voltage (VIN) Range
  • 2-7A Continuous Output Current (IOUT)
  • 1.7μA Low Shutdown Supply Current
  • 18μA Sleep Mode Quiescent Current (IQ)
  • Symmetric VIN for Low EMI
  • FSS –Frequency Spread Spectrum
  • Power Good (PG) Output
  • External Soft Start (SS)
  • 100ns Minimum On Time (tON)
  • Selectable Advanced Asynchronous Mode (AAM) or Forced Continuous Conduction Mode (FCCM)


  • Common Footprint
  • Multiple current ratings to allow upgrading/downgrading depending on changing application needs
  • Low IQ (18uA) and shutdown currents
  • 50V Abs Max for high Vin Tolerance
  • Enhanced EMI performance
  • Available AEC100 in all versions


  • Industrial power systems
  • Automotive Power
  • POE systems
  • Battery pack powered devices