Dual Cool™ Package for High Power Density



As DC-DC applications, such as power modules, telecommunications and servers become more space-constrained; designers are looking for ever smaller devices to meet their design challenges. The thermal capability of these devices, however, is a vital concern. In order to meet the needs for high current capability, high efficiency and smaller form factors, Fairchild Semiconductor developed the Dual Cool™ packaging for MOSFETs. The Dual Cool package is a top-side cooling PQFN device that incorporates new packaging technology which enables additional power dissipation through the top of the package as well as the bottom. Dual Cool packaging features an exposed heat slug that delivers a significant reduction in thermal resistance from junction to top of case, resulting in more than 60 percent higher power dissipation capability than standard PQFN packaging when a heat sink is mounted. Additionally, MOSFETs in the Dual Cool package are designed with Fairchild's proprietary PowerTrench® process technology, that enables lower RDS(ON) and higher load currents in smaller package sizes. Unlike competitive top-side cooling solutions, these devices are currently available in both Power33 (3.3mm x 3.3mm) and Power56 (5mm x 6mm) Dual Cool packaging options. Maintaining the same industry-standard PQFN footprint, the Dual Cool package allows power engineers to rapidly qualify MOSFETs in Dual Cool packaging, gaining increased thermal efficiency without the need to adjust for non-standard packages. Devices currently available in the Dual Cool package include the FDMS2504SDC, FDMS2506SDC, FDMS2508SDC, FDMS2510SDC (5mm x 6mm footprint) and the FDMC7660DC (3.3mm x 3.3mm footprint). These devices are ideal as synchronous rectifying MOSFETs for DC-DC converters, telecom secondary side rectification and high end server/workstation applications. Fairchild's Dual Cool packaged MOSFETs' top-side cooling and an ultra-low junction temperature (Rthja) enable increased thermal efficiency. MOSFETs in the Dual Cool package can be used with or without a heat sink. These Dual Cool packaged MOSFETs are part of Fairchild's industry-leading MOSFET portfolio. By understanding the demands for higher current DC-DC power supplies in smaller footprints for space constrained applications, as well as the company's customers and the markets they serve, Fairchild can tailor its unique combination of functional, process and packaging innovation into solutions that make a real difference in electronic designs. With this enhanced dual path thermal performance and improved parasitics over its wire-bonded predecessors, the use of a heat sink with Dual Cool packaging provides even more impressive results. Test results show a heatsinked Dual Cool package allows synchronous Buck converters to deliver higher output current, thus increasing power density. With Fairchild's world-class trench silicon technology, Dual Cool packaging proves to be a clear leader in power density and thermal performance. For more information on Fairchild's Dual Cool package, visit: www.fairchildsemi.com/dualcool