2.7V to 5.5V Input, 3.0A Integrated MOSFET Buck DC/DC Converter

BD9B300MUV is a synchronous buck switching regulator with built-in low on-resistance power MOSFETs. This IC, which is capable of providing current up to 3A, features fast transient response by employing constant on-time control system. It offers high oscillating frequency at low inductance. With its original constant on-time control method which operates low consumption at light load, this product is ideal for equipment and devices that demand minimal standby power consumption.

Data Sheet Buy * Sample *
* This is a standard-grade product.
For Automotive usage, please contact Sales.

Product Detail

Part Number | BD9B300MUV-E2
Status | Recommended
Package | VQFN016V3030
Unit Quantity | 3000
Minimum Package Quantity | 3000
Packing Type | Taping
RoHS | Yes






Integrated FET / Controller

Integrated FET



Synchronous / Nonsynchronous












SW frequency(Max.)[MHz]


Light Load mode






Operating Temperature (Min.)[°C]


Operating Temperature (Max.)[°C]


Package Size [mm]

3x3 (t=1)


  • Synchronous Single DC/DC Converter
  • Constant on-time control suitable to Deep-SLLM
  • Over Current Protection
  • Short Circuit Protection
  • Thermal Shutdown Protection
  • Under Voltage Lockout Protection
  • Adjustable Soft Start
  • Power Good Output
  • VQFN016V3030 Package (backside heat dissipation)


    • Evaluation Board
    • BD9B300MUV-E2EVK-101
    • This evaluation board has been specifically developed to evaluate the BD9B300MUV synchronous buck DC/DC converter with integrated 35mΩ Pch high-side and Nch low-side power MOSFETs. Features include up to 3A output and variable switching frequency: 1MHz (FREQ pin connected to VIN) or 2MHz (FREQ pin connected to ground).

  • User's Guide Purchase Inquiry
    • Evaluation Board
    • BD9B300MUV-EVK-001
    • BD9B300MUV-EVK-001 Evaluation board delivers an output 1.2 volts from an input 2.7 to 5.5 volts using BD9B300MUV, a synchronous rectification step-down DC/DC converter integrated circuit, with output current rating of maximum 3A. It offers high efficiency in all load ranges by equipping the efficiency improvement function in light-load.

  • User's Guide Buy

Design Resources



White Paper

  • Cutting-Edge Web Simulation Tool “ROHM Solution Simulator” Capable of Complete Circuit Verification of Power Devices and Driver ICs

User's Guide

  • Evaluation Board User's Guide for BD9B300MUV-EVK-001
  • Evaluation Board User's Guide for BD9B300MUV-E2EVK-101
  • Evaluation Board Data

Application Note

  • PCB Layout for BD9B300MUV

Reference Design

  • BD9B300MUV Reference Circuits and Bomlist

Technical Articles

Schematic Design & Verification

  • Buck DC/DC Converter Recommended Inductor List
  • Calculation of Power Dissipation in Switching Circuit
  • Considering Input Filter to Reduce Conducted Emissions by DCDC Converter
  • Considering Polarity of Power Inductor to Reduce Radiated Emission of DC-DC converter
  • Method for Monitoring Switching Waveform
  • PCB Layout Techniques of Buck Converter
  • Phase Compensation Design for Current Mode Buck Converter
  • Bootstrap Circuit in the Buck Converter
  • Method for Determining Constants of
  • Power Supply Sequence Circuit with General Purpose Power Supply IC
  • Suppression Method of Switching Noise Using Linear Regulator and Low Pass Filter
  • Measurement Method for Phase Margin with Frequency Response Analyzer (FRA)
  • Usage of SPICE Macromodel for DC/DC
  • Snubber Circuit for Buck Converter IC
  • Efficiency of Buck Converter
  • Calculation of Power Loss (Synchronous)
  • Inductor Calculation for Buck converter IC
  • Considerations for Power Inductors Used for Buck Converters
  • Capacitor Calculation for Buck converter IC
  • The Important Points of Multi-layer Ceramic Capacitor Used in Buck Converter circuit
  • Resistor Value Table to set Output Voltage of Buck Converter IC
  • Importance of Probe Calibration When Measuring Power: Deskew
  • Impedance Characteristics of Bypass Capacitor

Thermal Design

  • What Is Thermal Design
  • Basics of Thermal Resistance and Heat Dissipation
  • Method for Calculating Junction Temperature from Transient Thermal Resistance Data
  • Notes for Temperature Measurement Using Thermocouples
  • Two-Resistor Model for Thermal Simulation
  • Notes for Temperature Measurement Using Forward Voltage of PN Junction
  • Thermal Resistance
  • Precautions When Measuring the Rear of the Package with a Thermocouple



  • VQFN016V3030 Footprint / Symbol
  • VQFN016V3030 3D STEP Data

Packaging & Quality

Package Information

  • Package Information
  • Anti-Whisker formation

Manufacturing Data

  • Factory Information

Environmental Data

  • UL94 Flame Classifications of Mold Compound
  • Compliance with the ELV directive
  • REACH SVHC Non-use Declaration
  • RoHS Comission Delegated Directive

Export Information

  • The Export Control Order
  • Export Administration Regulations(EAR)