ROHM’s Industry-first* AC/DC Converter ICs of Surface Mount Package with Built-In 1700V SiC MOSFET

June 17th, 2021

*ROHM June 17, 2021 study


ROHM announces the AC/DC converter ICs with a built-in 1700V SiC MOSFET, BM2SC12xFP2-LBZ in the TO 263-7L package, optimized for industrial applications focusing on auxiliary power supplies for street lamps, commercial air-conditioning systems, general-purpose inverters and for AC servos drives.

An auxiliary power supply is an essential and vital part of industrial applications to deliver different levels of DC voltages for gate drivers and control units. By applying existing Si MOSFET devices, the designer cannot achieve higher efficiency and increased out power because of the higher losses of Si devices. The existing solutions require a heatsink and additional components which increase both the losses of the devices and also the size of the system by additional space. To design an auxiliary power supply with existing Si devices will also be expensive because of a larger Bill of Material (BOM).

ROHM’s BM2SC12xFP2-LBZ power ICs are the Quasi-resonant (QR) AC/DC converters with an integrated 1700V SiC MOSFET in a single compact surface mount package (TO263). These ICs are the right fit and best in class products for industrial auxiliary power supply solutions in terms of efficiency, shortening design time, simplifying the circuitry and reducing additional components by offering integrated solutions. These ICs also increase product reliability by minimizing the risk of component failure.

When used in 400VAC 48W output auxiliary power supplies, besides enabling automatic board mounting that was not previously possible, the number of external parts can be significantly reduced compared with standard configurations – from 12 parts and heat sink to just one.

At the same time, adopting a SiC MOSFET improves power efficiency by up to 5% and minimizes the risk of component failure. This makes it possible to dramatically increase reliability and energy savings in industrial equipment while significantly reducing mounting area and costs.

In addition, ROHM’s Evaluation board BM2SC123FP2-EVK-001 using our AC/DC BM2SC123FP2-LBZ IC is available to support designers. This board delivers power up to 48W at 400VAC without any heatsink. The test result of the evaluation board shows the output voltage (24V) is constant and independent from input voltage.

ROHM leads the industry in developing ICs that maximize the performance of SiC power semiconductors, including the offering of through-hole package AC/DC converter ICs equipped with a high voltage, low-loss SiC MOSFET in 2019.

ROHM is committed to continuing to develop advanced analog control ICs and power semiconductors, such as SiC devices, while providing optimized solutions that contribute to greater energy savings and performance in industrial equipment.

Comparison of AC/DC Converter Solutions for Auxiliary Power Supplies

Key Features

The BM2SC12xFP2-LBZ incorporates a 1700V SiC MOSFET along with control circuitry optimized for auxiliary power supplies in industrial equipment (i.e. SiC MOSFET gate drive circuit) in a dedicated package developed specifically for the internal SiC MOSFET. This series offers numerous advantages by providing the following features.

Key Features

1. The industry’s first 48W class surface mount package significantly reduces factory mounting costs
ROHM’s new products adopt the TO263-7L surface mount package developed specifically for embedded SiC MOSFETs. Despite its small size, the novel package provides sufficient safety margin (package creepage distance) for handling high power, ensuring support for up to 48W (24V x 2A) output without a heat sink. What’s more, enabling automatic board mounting by machine (not possible in the past for products in this range), together with requiring fewer external parts, contributes to significantly reducing assembly costs.

2. Achieves breakthrough miniaturization by replacing 12 components and heat sink with a single product
This new product replaces up to 12 components (AC/DC converter IC, 800V SiC MOSFET x 2, Zener diode x 3, resistor x 6) and heat sink utilized for conventional discrete Si MOSFET configurations, dramatically reducing the number of external parts required. In addition, the high withstand voltage and superior voltage noise resistance characteristics of the internal SiC MOSFET make it possible to reduce the size of components used for noise suppression.

Application Circuit and Adoption Results

3. Reduces man-hours and risk while multiple built-in protection functions provide superior reliability
The BM2SC12xFP2 series reduces the man-hours required for component selection and reliability evaluation for the clamp and drive circuits while also minimizing component failure risk and simplifying the development load for SiC MOSFET adoption. In addition, overload protection (FB OLP), overvoltage protection (VCC OVP) for the supply voltage pin, and a high accuracy thermal shutdown function (TSD) (achieved through the built-in SiC MOSFET) are included, along with over current protection and secondary overvoltage protection functions. Incorporating multiple protection circuits for industrial power supplies that require continuous operation significantly improves system reliability.

Si vs SiC Efficiency Comparison in an AC/DC Converter

4. Maximizes SiC MOSFET performance to achieve dramatically improved power savings
The built-in gate driver circuit that drives the internal SiC MOSFET improves power conversion efficiency by as much as 5% over conventional Si MOSFET configurations by maximizing SiC MOSFET performance (ROHM May 2021 study). At the same time, a quasi-resonant method is adopted for the control circuit that enables operation at higher efficiency and lower noise than conventional PWM systems, minimizing the effects of noise in industrial equipment.


AC/DC Converter IC with Built-In SiC MOSFET Lineup

Part No. Package Supply Voltage Range MOSFET Operating Frequency VCC OVP FB OLP Operating Temp Range
NEWBM2SC121FP2-LBZ TO263-7L 15.0V to 27.5V SiC MOSFET 1700V (Max.) 1.12Ω 120kHz (Max.) Latch Auto Restart -40ºC to +105ºC
NEWBM2SC122FP2-LBZ Latch Latch
NEWBM2SC123FP2-LBZ Auto Restart Auto Restart
NEWBM2SC124FP2-LBZ Auto Restart Latch
BM2SCQ121T-LBZ TO220-6M Latch Auto Restart
BM2SCQ122T-LBZ Latch Latch
BM2SCQ123T-LBZ Auto Restart Auto Restart
BM2SCQ124T-LBZ Auto Restart Latch

Application Examples

  • General-purpose inverters
  • AC servos
  • PLCs (Programmable Logic Controllers)
  • Manufacturing equipment
  • Robots
  • Commercial air conditioners
  • Industrial lighting (i.e. street lamps)

Optimized for auxiliary power supply circuits handling indicators, fans, relays, and PLC’s in 400VAC industrial equipment


- IC: $7.20/unit (samples, excluding tax)
- Evaluation board (BM2SC123FP2-EVK-001): $238.80/unit

Sales Launch Date:
May 2021 (Samples), October 2021 (In Mass Production)

Online Distributors: Digi-Key, Mouser, and Farnell

**Scheduled to be released at other online distributors as well.


Online Distributors

  • Digi-Key
  • Mouser
  • Farnell

Product Lineup

Description Part No.
AC/DC Converters with Built-In 1700V SiC MOSFET BM2SC121FP2-LBZ
BM2SC123FP2-LBZ Evaluation Board BM2SC123FP2-EVK-001
BM2SC123FP2-LBZ Evaluation Board


SiC (Silicon Carbide), MOSFET (Metal Oxide Semiconductor Field Effect Transistor)
SiC is a compound comprised of silicon (Si) and carbon (C). It has shown to exceed the characteristics and limits of silicon when used as a semiconductor material. A MOSFET is a type of transistor - a basic semiconductor component. It acts as a switching device that can control the flow of current or ON/OFF operation by applying an external voltage.

AC/DC Converter
A type of power supply that converts voltage from AC (Alternating Current) to DC (Direct Current). Generally, AC flows from the outlet while most electronic devices operate on DC, necessitating electronic components for voltage conversion.

Auxiliary Power Supply
High power industrial equipment typically includes a main power supply circuit for operating the motor (primary machine) and a sub power supply circuit that powers the LED indicators, fans, relays, and control IC(s). This sub power supply circuit is considered an auxiliary power supply.

Power Semiconductor
A semiconductor used to convert voltage or current (depending on the application), whose performance is directly linked to the power efficiency of the system and/or device. This requires high voltage and current handling capability.