New Product Introduction

Rohm BD9S

BD9S series - ultra-compact automotive buck DC/DC converters

Rohm BD9S series sample image

BD9S series of automotive secondary buck DC/DC converters for assisted driving systems, which are requiring high reliability and low power consumption in a compact form factor, such as radars, cameras, and sensors used in ADAS.

Key features

  • Enable control and Output voltage indicator to improve system reliability
    These IC’s includes an enable function to adjust the startup time and a built-in output (Power Good function) indicating correct output voltage.

  • Class-leading miniaturization and efficiency
    For automotive-grade secondary buck DC/DC converters requiring greater miniaturization and high performance operation, a class-leading 2mm² size with full synchronous operation is offered, while the optimized design ensures the best-in-class* power conversion efficiency among functionally equivalent products (90% at 3.6V input/1.8V output).
    The current mode control loop with fixed 2.2MHz frequency fluctuations makes it possible to reduce the size of peripheral components and eliminate interference from the AM radio band. A dedicated light load mode improves efficiency in the lower current load region. The result is higher miniaturization and power savings in safe driving support modules.

  • Broad lineup includes output currents up to 4.0A
    ROHM offers ultra-compact models in output currents ranging from 0.6A to 4.0A. This contributes to model optimization and supports sudden system changes


Part No. Input Voltage Range Output Voltage Max. Output Current Output Voltage Precision Operating Frequency Operating Temperature Package
BD9S400MUF‑C 2.7V to 5.5V 0.8 to Vin*0.8 4.0A ±1.5% 2.2MHz
-40oC to 125oC VQFN16FV3030
(3.0 x 3.0 x 1.0mm)
BD9S300MUF‑C 3.0A
BD9S200MUF‑C 2.0A
BD9S100NUX‑C 0.8 to Vin 1.0A VSON008X2020
(2.0 x 2.0 x 0.6mm)
BD9S000NUX‑C 0.6A
**BD9S110NUX‑C 1.2V 1.0A
**BD9S111NUX‑C 1.8V 1.0A

**BD9S110NUX-C and BD9S111NUX-C are under development


  • ADAS sensors, cameras, and radars
  • Drive recorders
  • Other automotive applications requiring high efficiency, superior reliability, and greater compactness

Block diagram

Rohm MD9S block diagram

Related Documents

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