Vishay Announces New SkyFET Monolithic Power MOSFET & Schottky Diode

Vishay Intertechnology, Inc. released the first of its monolithic MOSFET and Schottky SkyFET® products to use the company’s latest TrenchFET® technology. Using TrenchFET Gen III silicon, the new Si4628DY is said to deliver the lowest on-resistance ever for a device of its type in the SO-8 package, with a maximum r_DS(on) of 3mΩ at a 10V gate drive and 3.8mΩ at 4.5V.

The new Si4628DY SkyFET will typically be used as the low-side power MOSFET in synchronous buck converters for notebook core voltage and VRM applications, graphic cards, point-of-load power conversion, and synchronous rectification in computers and servers. Its on-resistance times gate charge figure of merit (FOM), a key indicator of performance in such applications, is said to be 26% better at a 10V gate drive and 34 % better at 4.5V than the next best device in the SO-8.

The Si4628DY is designed to improve power conversion efficiency at light loads for both mains-powered servers and battery-operated notebooks. Under light-load conditions, the MOSFET in power converters is off, and current is conducting through the Schottky diode. Because the Schottky is integrated with the MOSFET, its forward voltage drop is much lower than the voltage drop across the intrinsic body diode of the MOSFET. This results in substantially less power loss when the MOSFET is turned off during dead time in a buck converter application.

A second improvement results from the lower reverse recovery charge (Q_RR) of the Schottky diode compared with the Q_RR of the body diode of the MOSFET. Vishay claims that its SkyFET technology reduces Q_RR in the device by almost 75% from the standard MOSFET body diode, improving converter efficiency at light loads.

Finally, integration of the Schottky into the MOSFET silicon chip eliminates the parasitic inductances that would be present if these were mounted to the PCB as individual components or if separate MOSFET and Schottky diode components were co-packaged.

Samples and production quantities of the Si4628DY are available now, with lead times of 10 to 12 weeks for larger orders. Pricing for U.S. delivery starts at $0.48 in 100,000-piece quantities.