Renesas Technology America, Inc. announced the RJK0383DPA, a dual-type power MOSFET that enables smaller, higher-efficiency synchronous-rectification DC/DC converters for generating various supply voltages in communication devices and laptop PCs. The advanced, tenth-generation device integrates high-side and low-side power MOSFETs and a Schottky barrier diode in a compact (5.3×6.2×0.8mm, max) package with high thermal conductivity. In a synchronous-rectification circuit converting a 12V DC input to a 1.1V DC output at 600 kHz switching frequencies, it achieves an industry-best efficiency rating of 91.6 percent. Output current doubled from earlier dual-type power MOSFETs from Renesas Technology.
The higher power supply efficiency of the RJK0383DPA has two important benefits. It uses a small WPAK3 package that reduces the chip mounting area to about half that of a dual-package power MOSFET configuration, offering the same level of power supply efficiency. It also allows the device to deliver more output current. Smaller synchronous-rectification DC/DC converters are thus enabled, facilitating the higher mounting densities eagerly sought in mobile devices and other products in which small size adds convenience.
Evolution of solutions for improved synchronous-rectification DC/DC converters
Multiple synchronous-rectification DC/DC converters have become necessary in many types of electronic products. One of the main reasons for this is because the power consumption of successive generations of individual microchips has increased in recent years due to greater functionality, higher performance and the need to handle greater volumes of data. This led to demand for synchronous-rectification DC/DC converters specified for lower voltages and higher currents. But problems surfaced as the number of power MOSFETs used in a single system increased, so Renesas boosted the performance and improved the packages of its power MOSFET products.
“A two-package configuration made it possible to raise the power-supply efficiency of synchronous-rectification DC/DC converters so the output current could be increased without adding more power MOSFETs,” said Tetsuo Sato, director, solutions business unit, Renesas Technology America. “On the other hand, dual-type products that integrate two power MOSFETs in a single package have the advantage of having a smaller mounting area. However, the power-supply efficiency of these dual-type products was not as good as that of two-package configurations, so their maximum output current was lower. The market clearly desired a dual-type power MOSFET product with improved power supply efficiency and more output current to meet the space limitations of mobile devices. The new RJK0383DPA device directly addresses this need.”
The high-side power MOSFET in the RJK0383DPA has a drain-gate load (Qgd) of only 1.5nC (at VDD=10V) for a fast switching speed and correspondingly high efficiency. The device’s low-side power MOSFET has a low on-resistance (RDS (on)) of 3.7mO (typical, at 4.5V) that reduces power loss. Additionally, the device integrates a Schottky barrier diode (SBD) that is connected via low-inductance wiring to the low-side power MOSFET. This design speeds up the switching of current flow to the SBD during the DC/DC converter’s dead time, for less power loss. It also suppresses voltage spikes during switching, thereby reducing noise.
The advanced semiconductor manufacturing process that Renesas uses to fabricate the RJK0383DPA achieves lower loss and higher efficiency than the previous ninth-generation process. On-resistance is about 30 percent lower, while the opposing characteristics of gate charge capacitance (Qg) and drain-gate load (Qgd) are approximately 27 percent and 30 percent lower, respectively. (Both improvements are relative to earlier power MOSFET products with the same on-resistance.)
Besides the RJK0383DPA, Renesas is developing two other dual-type power MOSFETs having different output current ratings, the RJK0384DPA and RJK0389DPA. Further into the future, more products suitable for other DC/DC converter power supply specifications are under development in response to the needs of the market.
Price and Availability
RJK0383DPA dual-type power MOSFET – WPAK – $0.89 / Q4 2008
About Renesas Technology Corp.
Renesas Technology Corp. is one of the world’s leading semiconductor system solutions providers for mobile, automotive and PC/AV (Audio Visual) markets and the world’s No.1 supplier of microcontrollers. It is also a leading provider of LCD Driver ICs, Smart Card microcontrollers, RF-ICs, High Power Amplifiers, Mixed Signal ICs, System-on-Chip (SoC) devices, System-in-Package (SiP) products and more. Established in 2003 as a joint venture between Hitachi, Ltd. (TOKYO:6501) (NYSE:HIT) and Mitsubishi Electric Corporation (TOKYO:6503), Renesas Technology achieved consolidated revenue of 951 billion JPY in FY2007 (end of March 2008). Renesas Technology is based in Tokyo, Japan and has a global network of manufacturing, design and sales operations in around 20 countries with about 26,800 employees worldwide.