Nano Pulse Control™, QuiCur™, 2.7V to 5.5V, 4A 1ch 2.2MHz Synchronous Buck DC/DC Converter Integrated FET for Automotive

BD9S402MUF-C is a synchronous buck DC/DC converter with built-in low ON resistor power MOSFETs. It can provide current up to 4A. Small inductor is applicable due to high switching frequency of 2.2MHz. It has fast transient response performance due to current mode control. It has a built-in phase compensation circuit. Applications can be created with a few external components.

Product Detail

Part Number | BD9S402MUF-CE2
Status | Recommended
Package | VQFN16FV3030 (Wettable Flank)
Unit Quantity | 3000
Minimum Package Quantity | 3000
Packing Type | Taping
RoHS | Yes

Functional Safety:

Category : FS supportive
A product that has been developed for automotive use and is capable of supporting safety analysis with regard to the functional safety.




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)

Common Standard

AEC-Q100 (Automotive Grade)

Find Similar


  • QuiCur™
  • Nano Pulse Control™
  • AEC-Q100 Qualified(Grade 1)
  • Functional Safety Supportive Automotive Products
  • Single Synchronous Buck DC/DC Converter
  • Adjustable Soft Start Function
  • Output Discharge Function
  • Power Good Output
  • Under Voltage Lockout Protection(UVLO)
  • Short Circuit Protection(SCP)
  • Output Over Voltage Protection(OVP)
  • Over Current Protection(OCP)
  • Thermal Shutdown Protection(TSD)
  • Wettable Flank QFN Package

Supporting Information



The BD9S402MUF-C, in addition to meeting the basic requirements of secondary DC/DC converter ICs in ADAS for 2MHz or higher operation and 4A output current, ROHM’s unique Nano Pulse Control™ ultra-high-speed pulse control technology delivers next-generation low voltage output down to 0.6V – much lower than the typical 1.0V voltage output required by current SoCs and MCUs. At the same time, equipped QuiCur™ high-speed load response technology achieves extremely stable operation. The ability to suppress voltage output variation within 5% even at low output voltages below 1.0V makes it ideal for secondary power supplies for the latest ADAS.

The BD9S402MUF-C is also equipped with a load response performance selection function that leverages the characteristics of QuiCur™ technology, allowing users to easily switch priority between ‘voltage fluctuation’ (for industry-leading stable operation) and ‘capacitance reduction’ (to ensure stable operation at 22μF) by setting High/Low of the GAIN pin. For example, the user can set the GAIN pin to High in the case of a power supply for a high-performance SoC that needs to handle fast load fluctuations. Or the user can set the GAIN pin with Low for a good balance between performance and capacitor cost when the power supply for an MCU doesn’t need to consider high accurate voltage fluctuations. This contributes to a significant increase in design flexibility for application designers, as stable operation can be easily achieved at initial design as well as during specification or model changes.

Load Response Performance Selection Function Contributes
to Design Optimization and Reduced Resources

Application Examples

  • ◇ ADAS ECU, sensors, cameras, and radars
  • ◇ Communication systems including wireless modules and gateways
  • ◇ Infotainment systems such as clusters and head-up displays (HUDs)
    Along with secondary power supplies in automotive applications that employ high-performance SoCs, MCUs, and DDR memory, etc.

Reference Design / Application Evaluation Kit

    • Evaluation Board - BD9S402MUF-TSB-001
    • This Evaluation Board was developed for ROHM’s single Synchronous buck DC/DC converter BD9S402MUF-C. It has fast transient response performance due to current mode control, and the built-in QuiCur™ maximizes the response performance. It has a built-in phase compensation circuit. Applications can be created with a few external components.

  • User Guide

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