7.0V to 36V Input, 1.0A Integrated MOSFET Single Synchronous Buck DC/DC Converter

This product guarantees long life cycle in Industrial market. BD9E100FJ-LB is a synchronous buck switching regulator with built-in power MOSFETs. It is capable of an output current of up to 1.0A. It has a high oscillation frequency of 1MHz while using small inductance value. It is a current mode control DC/DC converter and features high-speed transient response. Phase compensation can also be set easily.

Product Detail

Part Number | BD9E100FJ-LBGE2
Status | Recommended
Package | SOP-J8
Unit Quantity | 2500
Minimum Package Quantity | 2500
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]

4.9x6 (t=1.65)


・Long Life Cycle Product for Industrial Applications.
・Synchronous single DC/DC converter.
・Over-Current Protection.
・Short Circuit Protection.
・Thermal Shutdown Protection.
・Undervoltage Lockout Protection.
・Soft Start.


    • Evaluation Board
    • BD9E100FJ-EVK-001
    • BD9E100FJ-EVK-001 Evaluation board delivers an output 5.0 volts from an input 7.2 to 33 volts using BD9E100FJ-LB, a synchronous rectification step-down DC/DC converter integrated circuit, with output current rating of maximum 1A. The output voltage can be set by changing the external parts of circuit and the loop-response characteristics also can be adjusted by the phase compensation circuit.

  • User's Guide Design Data Buy

Design Resources



White Paper

  • Industrial DC/DC Buck Converters BD9x Series
  • 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
  • Evaluation Board Data

Application Note

  • PCB Layout for BD9E100FJ-LB

Reference Design

  • BD9E100FJ-LB(E2) 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
  • 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
  • PCB Layout Techniques of Buck Converter
  • 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
  • Two-Resistor Model for Thermal Simulation
  • Notes for Temperature Measurement Using Thermocouples
  • Notes for Temperature Measurement Using Forward Voltage of PN Junction
  • Thermal Resistance
  • Precautions When Measuring the Rear of the Package with a Thermocouple


Simulations (Login Required)

ROHM Solution Simulator is a new web-based electronic circuit simulation tool that can carry out a variety of simulations, from initial development that involves component selection and individual device verification to the system-level verification stage. This makes it possible to quickly and easily implement complete circuit verification of ROHM power devices and ICs, in simulation circuits under close to actual conditions, significantly reducing application development efforts.
  • BD9E100FJ / Frequency Domain

Calculation Tools

This Calculation Sheet supports the application circuit design of switching regulators. The sheet has formulas necessary for determining peripheral parts. You can easily determine the circuit parameters that meet the desired characteristics by setting the values according to the guidance.
  • Calculation-sheet for the circuit theoretical formula - BD9Exxx-LB


  • BD9E100FJ-LB(E2) SPICE Model


  • SOP-J8 Footprint / Symbol
  • SOP-J8 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)