Rohm Semiconductor introduces MOSFETs capable of drive operation from 0.9V. Based on the company’s fabrication technology the ECOMOS devices exhibit a improvement in RDS(ON) values particularly when low gate voltages are required. This results in a power consumption which is up to 90% lower than in comparable devices such as bipolar transistors when operated at ultra-low voltages. As battery-driven portables become smaller the need for greater compactness and lower energy consumption continues to grow.

Many ICs are capable to operate from 1V or less due to their highly efficient circuitry. However, up to now the lowest drive voltage of MOSFETs required for external switching applications for ICs, has been at least 1.2V. Therefore it has been necessary to step up the voltage to 1.2V or higher using a boost circuit or bipolar transistor generating disadvantages such as high loss during driving, a complicated circuit design as well as reduced efficiency.

So far it has been difficult to lower the threshold voltage in MOSFETs due to current leakage at high temperatures and the difficulty in keeping MOSFETs off at drive voltages below 1.2V. By optimizing the MOSFET gate oxide layer and channel profile, Rohm has succeeded in controlling current leakage, making 0.9V drive possible with a stable OFF state. This enables operation using a single dry-cell battery (1.2V, termination voltage 0.9V) without requiring a step-up circuit.

Target applications are portable devices such as mobile phones, digital cameras, portable audio players, electronic dictionaries, IC recorders, smart phones, LED control, pre-drive blocks, solar batteries, muting circuits, low-side circuits and many more. The ECOMOS 0.9V line-up is available in a variety of package types, from VMN3 (0,6 mm x 1,0 mm) to UMT6 (SOT-363).