MOSFETs Boost DC-DC Converter Efficiency

Apr 20, 2005 2:04 PM

A power MOSFET chipset from Renesas Technology enables dc-dc converters to stepdown a 12-V input to a 1.3-V, 20-A output with 90% efficiency. That represents a 2.5% improvement in efficiency versus results obtained with previous Renesas MOSFETs.

The new chip set consists of the RJK0305DPB high-side MOSFET and the RJK0301DPB low-side MOSFET. These transistors are ideal for dc-dc converters that convert a 12-V or 19-V input to a 0.8-V to 2.5-V output. The improved performance of these MOSFETs is achieved through an advanced trench manufacturing process that has been tuned for the intended applications.

In the RJK0305DPB high-side device, drain-gate charge (Q_gd) has been lowered by approximately 15% from that of the previous Renesas MOSFETs. This enhancement reduces the switching loss experienced at higher frequencies. In addition, the RJK0301DPB features approximately 20% lower on-resistance than previous devices, which reduces conduction losses in the low-side FET. Both MOSFETs are packaged in the company’s LFPAK.

For the RJK0305DPB, other key specs include a max V_DSS of 30 V and a max I_D of 30 A. R_DS(on) for this device at a V_GS of 4.5 V is 8.4 mΩ, typ and 11.0 mΩ, max, while Q_gd is 2.2 nC.

For the RJK0301DPB, other key specs include a max V_DSS of 30 V and a max I_D of 60 A. R_DS(on) for this device at a V_GS of 4.5 V is 2.7 mΩ, typ and 3.5 mΩ, max, while Q_gd is 8.0 nC.

Renesas Technology will continue to extend its line of power MOSFET products employing the newly developed process. The development of SOP-8 mounted models is underway, as are 60-V and 100-V V_DSS products. These future devices will expand the range of applications to encompass isolated dc-dc converters.

Pricing for the RJK0305DPB is $1 each in quantities of 10,000, with samples available starting in June. Pricing for the RJK0301DPB is $1.50 each in quantities of 10,000 with samples available starting in June.

For more information, visit www.renesas.com.

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