EL SEGUNDO, CA. January 1997 - International Rectifier, the leading global supplier of semiconductors for power conversion applications, now offers a line of low charge HEXFET power MOSFETs that improve the switching efficiency and reduce gate driver requirements in a wide range of applications, including power supplies, solid-state lighting ballasts and DC-DC converters.

The low charge nature of these new devices results from several modifications to the standard IR HEXFETs process. By using a narrower poly line width, thicker gate oxide, and lower channel implant, Miller capacitance is reduced by 85 percent and gate charge goes down by 40 percent. This cuts MOSFET switching losses in half.

As an added benefit, the thicker oxide of the low charge HEXFET increases gate voltage rating by 50 percent to ±30 V.

"Our low charge HEXFETs offer designers significant improvements in terms of lower overall systems cost," said Arnold Alderman, Director of Industrial Marketing at IR. "The gate capacitance reduction directly lowers gate drive requirements, so low cost drivers can be used in power supplies and ballasts, even for larger MOSFETs . The reduced switching losses provide higher efficiency for applications like DC-DC converters, and the faster switching times permit operation at extremely high frequencies, 1 MHz or more, in these applications," he added.

IR's low charge IRF840LC HEXFET exhibits a typical gate charge of just 39 nC, a major reduction from the 63 nC gate charge of most other MOSFETs. A wide range of low charge devices is available for varying voltage and current ratings. Typical devices include the 400-V IRF740LC rated at 10 Amps, the 500-V IRF840LC rated at 8 Amps and the 600-V IRFBC40LC rated at 6.2 Amps. All devices are available off-the-shelf in TO-220 packages.

Contact the Technical Assistance Center or your local Sales Rep.