Renesas Technology to Release RJK0383DPA Dual-Type Power MOSFET Delivering Higher Power Supply Efficiency in D

Renesas Technology to Release RJK0383DPA Dual-Type Power MOSFET Delivering Higher Power Supply Efficiency in DC/DC Converters for Products Such as Laptop PCs and Communication DevicesHeadline

− Enables more compact power supply designs through reduction of chip mounting area to half that a existing dual-package configuration using Renesas power MOSFETs −

Tokyo, July 14, 2008 −− Renesas Technology Corp. today announced the RJK0383DPA dual-type power MOSFET for synchronous rectification DC/DC converters for memory or ASICs in products such as laptop PCs and communication devices. It achieves higher power supply efficiency. Sample shipments will begin in October 2008 in Japan .

RJK0383DPA incorporates dual power MOSFETs of two different types, composing a synchronous rectification DC/DC converter in a WPAK*1 (Renesas Technology package code) high-thermal-radiation package measuring 5.1 x 6.1 mm and 0.8 mm thick (max.)

The features of the RJK0383DPA are summarized below.

(1) Advance process delivering outstanding power supply efficiency of 91.6%

The RJK0383DPA achieves higher power supply efficiency by using state-of-the-art 10th-generation power MOSFETs. For example, power supply efficiency when converting 12 V input to 1.1 V output is 91.6% (at 600 kHz switching frequency), the best in the industry. Power supply output current that power MOSFETs handle increases double from earlier dual-type products from Renesas Technology.

(2) Enables more compact power supply design and higher mounting density through reduction of chip mounting area to half that of earlier dual-package power MOSFET configurations

By achieving higher power supply efficiency, the RJK0383DPA reduces the chip mounting area to about half that of a dual-package power MOSFET configuration, enabling a more compact synchronous rectification DC/DC converter and higher mounting density. The RJK0383DPA will be particularly effective for applications requiring compactness, such as mobile devices.

The RJK0383DPA will be followed by two additional products having different output current ratings, the RJK0384DPA and RJK0389DPA. Sample shipments of these will also begin in October 2008 in Japan .

In a typical communication device or information device such as a laptop PC or graphics card, components such as the memory, ASICs, and graphics processing unit (GPU) each employ a different power supply voltage. This requires use of multiple Synchronous rectification DC/DC converters. In addition, the power consumption of individual microchips has increased in recent years due to higher functionality and performance as well as an increase in the volume of data handled. This has generated demand for synchronous rectification DC/DC converters with lower voltage and higher current specifications. Problems arise as the number of power MOSFETs used in a single system increases.

In response, Renesas Technology has boosted the performance and made improvements to the package configuration of its power MOSFET products. By raising the power supply efficiency of the synchronous rectification DC/DC converter through the use of a two-package configuration, it was possible to boost the power supply output current without increasing the number of power MOSFETs. In addition, Renesas Technology developed and mass produced dual-type products that integrate two power MOSFETs in a single package and thereby reduce the mounting area. However, because of heat dissipation issues the power supply efficiency of the dual-type products was not as good as that of two-package power MOSFET configurations, and current output was lower. The market clearly desired a dual-type power MOSFET product with improved power supply efficiency to meet the compactness requirements of mobile devices.

The new RJK0383DPA is a dual-type power MOSFET fabricated using a low-loss state-of-the-art 10th-generation process. It delivers power supply efficiency approximately 7% higher than earlier dual-type products from Renesas Technology.

The RJK0383DPA integrates dual power MOSFETs of two different types, one as the high-side element and the other as the low-side element.*2 The high-side power MOSFET has a drain-gate load (Qgd) of 1.5 nC (at VDD=10V) to provide high switching speed and correspondingly high efficiency. The low-side power MOSFET has a low on-resistance*3 (RDS (on)) of 3.7 mΩ (typ. : at 4.5 V) to reduce power loss.

In addition, the low-side power MOSFET is integrated on the same chip as the schottky barrier diode (SBD) to minimize the wiring inductance*4 between them. This speeds up the switch of current flow to the Schottky barrier diode during the DC/DC converter’s dead time, further reducing loss. It also has the effect of suppressing voltage spikes during switching, thereby reducing noise.

The 10th-generation process used to fabricate the RJK0383DPA achieves lower loss and higher efficiency than the 9th-generation process that preceded it. On-resistance is about 30% lower while the opposing characteristics of gate charge capacitance (Qg) and drain-gate load (Qgd) are approximately 27% and 30% lower, respectively (both in comparison with earlier power MOSFET products having the same on-resistance).

The RJK0383DPA will be followed by two additional products having different output current ratings, the RJK0384DPA and RJK0389DPA. In future more products suitable for other DC/DC converter power supply specifications will be added to the series in response to the needs of the market.

Notes: 1. WPAK high-thermal-radiation package: In a power MOSFET, heat is generated due to on-resistance, switching, and similar loss factors. The amount of current that can be controlled is determined by how efficiently this heat can be released. The structure of a WPAK package allows heat dissipation to the board from a heat-dissipating die pad on the rear surface, enabling a larger current to be controlled.

2. High-side and low-side elements: These elements are used as non-insulating DC-DC converter switches, enabling voltage conversion to be performed by means of alternate on/off switching between the high side and low side. For the high-side on-period a short pulse of approximately 10% of one cycle is controlled, and the remaining 90% is the on-period of the low-side element, so an element whose characteristics emphasize switching speed is selected for the high-side element, and an element whose characteristics emphasize low on-resistance is selected for the low-side element.

3. On-resistance: The operational resistance of a power MOSFET. On-resistance is the parameter that most affects power MOSFET performance, with performance increasing as on-resistance decreases.

4. Wiring inductance: Parasitic inductance that is naturally present in wiring and has a value approximately proportional to the length of the wiring. The larger this value, the longer the current switching time between the power MOSFET and schottky barrier diode and the greater the switching loss.

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