Renesas Electronics - Power MOSFET Products that Realize High-Efficiency DC/DC Converters

The new products are used to control the voltage-conversion circuits of the CPU and the memory. For example, the new power MOSFETs can be used as a step-down circuit for converting the 12-volt (V) voltage supplied by a battery to 1.05 V for use by the CPU. Further refinements to the manufacturing process allow Renesas Electronics’ new MOSFETs to achieve approximately 40 percent lower FOM (figure of merit; on-state resistance times gate charge, Note 1) compared to the company’s existing products, which contribute to reduction of the power loss during voltage conversion and thereby enable highly efficient DC/DC converter performance.

As the performance of applications such as servers, notebook PCs, and graphics cards increases, their power consumption grows. At the same time the trend toward lower operating voltages for components such as CPUs, graphics processing units (GPUs), memory, devices and ASICs results in increased current flow. This creates a need for DC/DC converters capable of handling low voltages and large currents. In addition, there is strong demand for reduced power loss during voltage conversion and higher efficiency to help conserve energy and reduce environmental impact. Renesas Electronics is addressing these demands by expanding its lineup of low-FOM power MOSFET product offerings with its new products that achieve the leading level of performance in the industry today.

With a voltage tolerance (VDSS) of 25 V, the new products achieve maximum current (ID) of 40 amps (A) for the RJK0210DPA MOSFET, 30 A for the RJK0211DPA device, and 25 A for the RJK0212DPA device, and their FOM (typical values at VGS = 4.5 V) are 6.84 mΩ∙nC, 7.83 mΩ∙nC, and 7.2 mΩ∙nC, respectively, which is an improvement of approximately 40 percent compared to Renesas Electronics’ MOSFETs.

In addition, the new products’ gate-drain charge capacitance (Qgd), a key characteristic of control power MOSFETs, is 1.2 nC, 0.9 nC, and 0.6 nC, respectively, which also is approximately 40 percent less than Renesas Electronics’ generation power MOSFETs (when measured using the same on-resistance). Lower figures indicate less switching loss, contributing significantly to more efficient DC/DC converter performance and improved energy efficiency.

A DC/DC converter operates by having two power MOSFETs, one for control and the other for synchronous rectification, switching on and off alternately to convert the voltage. When the new RJK0210DPA MOSFET is used for control and the Renesas Electronics 11th generation RJK0208DPA device for synchronous rectification, the maximum power conversion efficiency is 90.6 percent at an output current level of 18 A and 86.6 percent at an output current level of 40 A, when converting from 12 V to 1.05 V. (Both figures are based on a switching frequency of 300 kHz and a two-phase configuration).

These new MOSFETs use the Renesas Electronics WPAK package, which measures 5.1 × 6.1 millimeters (mm) and 0.8 mm (maximum) thick. The underside of the device has a die pad that allows heat to pass to the printed wiring board while the power MOSFET is operating and enables the power MOSFET to handle large currents.

Renesas Electronics will continue to develop semiconductor products suitable for DC/DC converters of various types, aiming for low loss and high efficiency, in order to contribute to the development of more compact systems that use less energy.