The Industry's First 0.9V Drive MOSFETs


ROHM Co., Ltd. has announced the expansion of its ECOMOSTMseries of low voltage drive MOSFETs with the industry's first 0.9V type – ideal for mobile devices, including portable audio, IC recorders, electronic dictionaries, portable radios, and electronic toys.

As portable, battery-driven devices become smaller the need for greater compactness and lower energy consumption continue to grow. A greater number of products can now be driven by a single dry-cell battery, with many ICs capable of operation from 1V or less, due in large part to the increasing efficiency of the internal circuitry. However, up to now the lowest drive voltages of MOSFETs, which are required for external switching applications for ICs, is at least 1.2V. Therefore, in order to add an ON/OFF switch to a drive line of 1.2V or less it has been necessary to step up the voltage to 1.2V or higher using a boost circuit or bipolar transistor. Unfortunately, this method entails numerous drawbacks, such as high loss during driving and a more complicated circuit design. Efficiency is also reduced, increasing the need for a sub-1V drive MOSFET. However, it has been difficult to lower the threshold voltage in MOSFETs due to current leakage at high temperatures and the difficulty in keeping the MOSFET OFF at drive voltages below 1.2V.

ROHM has succeeded in controlling current leakage by optimizing the MOSFET gate oxide layer and the channel profile, 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, contributing to smaller, lighter sets with fewer external parts and significantly lower power loss – up to 90% less compared with bipolar transistors.

Pricing : 10yen/unit (For sample shipments)
Availability : February 2010 (OEM Quantities)

Key Features

  • Compatible with 0.9V drive
  • Capable of being driven with a single dry-cell battery
  • Drive loss reduced by up to 90% compared with bipolar transistors

Characteristics Graph

Characteristics Graph


Package PD(W) Polarity Part No. VDSS(V) ID(A) RDS(on) typ.(Ω)
VGS=0.9V VGS=1.2V VGS=2.5V
VMN3 0.15 Nch RYB002N05 50 0.2 3.0 2.2 1.7
VMT3 0.15 Nch RYM002N05
EMT3 0.15 Nch RYE002N05
EMT6 0.15 Nch+Nch EM6K34
UMT3 0.2 Nch RYU002N05
UMT6 0.15 Nch+Nch UM6K34N