Renesas Technology Corp. has long been committed to preserving and protecting the natural environment, and the development of products complying with the EU RoHS Directive (Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment) and China RoHS (Management Methods for Controlling Pollution by Electronic Information Products) is an integral part of this effort. Work to eliminate lead from products began early on, and it has now become possible to offer lead-free versions of most products, even for fields not covered by the RoHS Directive. Renesas Technology is also proceeding with efforts to eliminate halogens, which are considered to have an adverse environmental impact. One example is the RJK0383DPA lead-free and halogen-free power MOSFET. It is a power MOSFET device for use in synchronous rectification DC/DC converters for memory or ASICs in products such as laptop PCs and communication devices. It integrates high-side and low-side MOSFETs and a Schottky barrier diode in a single package. This product employs a WPAK ultrathin and high-thermal-radiation package that achieves low thermal resistance.
The package is offered entirely lead-free by employing Ag paste for die attach as well as using lead-free plating for terminals. In addition, the plastic mold used in the package of the RJK0383DPA contains metallic hydroxide compounds rather than the halogen Br/Sb, which was employed previously. This makes the product entirely halogen-free. Even with the switch to metallic hydroxide compounds, the plastic mold is certified V-0 under the UL94 Standard, and provides reliability and physical properties equivalent to plastic mold containing Br/Sb.
 The RJK0383DPA also has an improved element with enhanced characteristics, contributing to higher power supply efficiency and reduced energy consumption. As the functions, performance, and data processing volume of products such as laptop PCs have advanced in recent years, the amount of power consumed by the microchips they contain has increased, creating a need for better power supply efficiency and reduced loss. This has boosted demand for power MOSFET products having a high-side element with high-speed switching and a low-side element with low on-resistance to make possible DC/DC converters having lower voltage and larger current specifications. To meet these requirements, the RJK0383DPA uses a 10th-generation process which achieves lower loss and higher efficiency than the 9th-generation process that preceded it. 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 in comparison with earlier power MOSFET products having the same on-resistance).
These improvements enable the RJK0383DPA to achieve high-speed switching for the high-side element and low on-resistance for the low-side element, as shown in the Figure, for industry top-level power supply efficiency of 92.6 percent (Vin = 12V, Vout = 1.2V, fsw = 300kHz) and reduced energy consumption.
|
