ROHM Develops TVS Diode for New RASMID Lineup

ROHM Co., Ltd. announced that it has developed the industry's smallest TVS diode (VS3V3BxxFS series) with a size of 0.4×0.2mm to meet the growing demand for smartphones and wearable devices.

The company explained that this product, a type of ROHM’s world’s smallest component RASMID (ROHM Advanced Smart Micro Device) series, reduces the area by 56% and the volume by 81% compared to the existing size (0.6×0.3mm), contributing to high-density mounting for smartphones and the like.


Recently, there has been an increasing demand for miniaturization and longer battery life in mobile devices such as smartphones and wearable devices. In addition, Zener diodes and low-capacity protection diodes are used in various electronic devices to protect electronic circuits from electrostatic discharge (ESD). With the increasing functionality of devices, there is a demand for compact size and high ESD protection capabilities, leading to a growing demand for TVS diodes, which offer a wider range of warranty coverage compared to other diodes.

Under these circumstances, ROHM is realizing miniaturization by using a completely new manufacturing process different from existing ones, and is expanding the lineup of the RASMID series, the world's smallest component with high dimensional accuracy (±10μm).

In addition, the chip sides of the RASMID series employ proprietary dicing processing technology, resulting in a dramatically smoother surface compared to conventional products, thereby making them resistant to external impacts and improving fracture strength. Furthermore, an insulating film is applied to the smooth sides to prevent leakage caused by accidental solder balls.

Recently, there has been an increasing demand for low-voltage circuits to extend battery life. While suppressing leakage current has been a challenge to achieve miniaturization and reduce the standoff voltage directly associated with low-voltage circuits, the newly developed RASMID series TVS diode achieves both low leakage current and low voltage simultaneously through the fusion of Zener breakdown and bipolar technologies. By achieving a standoff voltage (VRWM) of 3.3V, it contributes to energy saving in devices.

Through structural optimization, high ESD protection capability equivalent to existing 0603 size 5.0V products has been secured. In addition to miniaturizing components, it is possible to reduce the load applied to the application by preventing circuit destruction and malfunction caused by static electricity.

ROHM plans to make a full-scale entry into the TVS diode market by adding a new TVS diode to its series to meet the demands of low-voltage circuits. Sample shipments of this product began in October, and mass production is scheduled to start in January 2016 with a production capacity of 5 million units per month. Both the front-end and back-end processes are manufactured at ROHM Apollo Co., Ltd. (Fukuoka).