ROHM’s New Compact Intelligent (Smart) Low Side Switches: Reduced Power Loss and Safer Operation Using Proprietary TDACC™ Circuit and Device Technology
Replaces mechanical relays and MOSFETs fulfilling functional safety requirements in the automotive and industrial equipment applications

*ROHM February 7th, 2023 study


ROHM released a new generation of 1 channel and 2 channel 40 V Intelligent (Smart) Low Side Switches : the BV1LExxxEFJ-C and BM2LExxxFJ-C series. The two product families are ideally designed for automotive and industrial applications. They are AEC-Q100 qualified and are suitable for systems such as car body control, engine and transmission control units, LED lighting modules or industrial PLC (programmable logic controllers).

The growing number of electronic components and digitalization of various type of equipment is driving the need to shrink the application solution size and to reduce the bill-of-materials (BOM). Besides, global issues such as CO2 emissions, or global trends such as autonomous driving, lead to stricter requirements and more complex architectures that demand an increased safety and robustness level. Conventional discrete solutions involving mechanical relays or MOSFETs can no longer meet these requirements and cannot provide protection against system failures. With greater demand for high integration, added safety features, build-in intelligence and diagnostic features, Intelligent Power Devices (IPD), also called smart switches, become an essential part for electronic systems in a continuously growing market.

ROHM addressed these market needs early on – by having developed a dedicated Smart Power process in 2014. Bringing together innovation, power efficient technology, process optimization and analog design experience, allows ROHM to offer a broad lineup of high-performance products. The integrated over-temperature, over-current and over-voltage protections, built-in diagnostic features and micro-controller feedback grant enhanced performance and reliability, superior lifetime and reliability over discrete solutions.

Structural Comparison of Power MOSFET in Smart Switch: Standard Product vs ROHM’s Original TDACC™

The BV1LExxxEFJ-C and BM2LExxxFJ-C family of products are Intelligent Low Side Devices that integrated all of the above and can switch currents for any type of resistive, capacitive or inductive loads. When switching off an inductive load, the power MOSFET inside the smart switch needs to dissipate all the magnetic energy stored previously in the inductor’s magnetic field. During this time the device protects itself by actively clamping the voltage to a safe level. The power dissipated, generates heat that is distributed on the integrated power MOSFET’s surface. ROHM’s new products are the industry’s first* to combine heat suppression with low ON resistance (difficult to achieve in a compact size), by optimally controlling the number of current-carrying channels using proprietary TDACC™ circuit and device technology. TDACC™ offers increased integration capability, allowing ROHM to report the industry’s first* 2 channel 40mΩ (ON resistance) product in the compact SOP-J8 package.
A wide range of ON-resistance values (40/80/160/250mΩ) in both 1 channel and 2 channel configurations are offered to meet diverse customer needs. Furthermore, the contact discharge tolerance of all the products in the family is higher than that of other standard products. This adds to a safer operation inside various electronic equipment types.

Taking advantage of the TDACC™ technology, ROHM will continue to develop Intelligent Power Devices with lower ON resistance and a higher level of feature integration. This will allow ROHM to expand its product portfolio confirming its high-quality commitments towards customer needs with higher performance products, increased functionality, outstanding energy efficiency, cost reduction and higher safety.

Comparison of Contact Discharge

Tolerance: New vs Standard Products

Contact Discharge Tolerance Comparison:
BV1LExxxEFJ-C/ BM2LExxxFJ-C vs Standard Products

ROHM’s Intelligent Switch Lineup

ROHM‘s Intelligent Switch Lineup

New Product Lineup

Part No.Data
No. of ChON Resistance
Built In
Safety Category
FS supportive
(4.9 × 6.0 × 1.00)
(4.9 × 6.0 × 1.65)

*Indicates the automotive IC is able to support functional analysis related to safety analysis.

About the ComfySIL™ Brand

ROHM launched the ComfySIL™ brand of products for stakeholders and customers involved with functional safety design that can contribute to the safety, security, and comfort of social systems.
ComfySIL™ is awarded to products that conform to the ComfySIL™ concept for functional safety not only in the automotive field, but in the industrial equipment market as well.


ComfySIL™ Website

*ComfySIL™ is a trademark or registered trademark of ROHM Co., Ltd.

Application Examples

◇ BCMs (Body Control Modules), interior/exterior lamps, engine, transmission, and other automotive electrical systems
◇ Industrial equipment such as PLCs (Programmable Logic Controllers)
Suitable for a wide range of applications in addition to the automotive and industrial systems.

Online Sales Information

Sales Launch Date: February 2023
Pricing: $1.3/unit (samples, excluding tax)
Online Distributors: Digi-Key, Mouser, and Farnell
Scheduled for release at other online distributors as well.

Online Distributors

  • Digi-Key
  • Mouser
  • Farnel

Comparison with Common Switches

◇ vs. Mechanical Relays

vs. Mechanical Relays

◇ vs. MOSFETs


Comparison of Smart High Side / Low Side Switches

Comparison of Smart High Side / Low Side Switches


Intelligent Power Devices (IPD) / Smart Switches
Intelligent Power Devices are electronic circuits that control/switch electric power and are capable and rigid enough to self-protect and protect the load and the surrounding environment from failure or breakdown. They are either Low Side or High Side intelligent semiconductor-based power devices with build in protection and diagnostic functions. IPDs can be directly interfaced to a micro-controller and provide feedback. They can replace MOSFETs, relays or fuses and are suitable to drive/switch any resistive, inductive, capacitive, or LED type of load. The integrated protection features make IPDs stronger, safer and higher quality products.
Back Electromotive Force
Electromotive force manifesting as a voltage, generated by inductive loads such as motors and coils, which oppose changes in the initial magnetic field. This is due to Lenz’s Law.
Thermally Distributed Active Clamp Control. ROHM’s original circuit and device technology that achieves both heat suppression and low ON resistance by optimally controlling the number of current-carrying channels when the power MOSFET in the smart switch generates heat due to back EMF during a turn off event.
*TDACC™ is a trademark or registered trademark of ROHM Co., Ltd.
ON Resistance
The effective resistance value between the Drain and Source of a MOSFET while in the ON state. The lower this value is, the lower the (power) loss during conduction.
Functional Safety
Functional safety includes safety measures (concepts for ensuring safety) that minimize risk by adding functionality such as monitoring together with protective equipment. Functional safety minimizes risk to an acceptable level to prevent bodily injury in the event of malfunction due to electronic system failure.


AEC-Q100 Qualified
Automotive-Grade IPD Low Side Switches (Intelligent Power Devices)
BV1LExxxEFJ (1ch) /BM2LExxFJ-C series (2ch) (PDF:610KB)