Alpha and Omega Semiconductor Limited, a designer, developer, and global supplier of a broad range of power semiconductors and power ICs, and digital power products, announced the release of 600V 110mOhm and 140mOhm αMOS5™ Super Junction MOSFETs in DFN8x8 Package. αMOS5 is AOS’s latest generation of high voltage MOSFET, designed to meet the high efficiency and high-density needs for Quick Charger, Adapter, PC Power, Server, Industrial Power, Telecom, and Hyperscale Datacenter applications.
Today’s Server Power design is driven by two major differentiators – high efficiency and a slim form factor to accommodate 1U, 0.5U, or even thinner systems. As higher power output is required while board space is further reduced, there are no other ways but choosing components with lower losses and small dimensions. Given the large stray inductance (larger Eon losses) and unfit height, the traditional through-hole package types are no longer the options. Typical high-power PFC and LLC stages also use gate drivers to control MOSFETs. Packages with Kelvin Sources will allow separate power and drive source connections, thus suppressing di/dt induced Vgs transients and turn-on losses. To further reduce system losses, other than minimizing magnetic and switching losses by leveraging ZVS/ZCS topologies, an increasingly adopted solution is to replace the diode bridge with high voltage MOSFETs, which serves as an Active Bridge Rectifer through the control of a driver (e.g., AOS AOZ7200).
AOS’s newly released AONV110A60 and AONV140A60 are two 600V low ohmic MOSFETs packaged in the 8mm x 8mm x 0.9mm DFN8x8 with Kelvin Source. Compared to other packages such as D2PAK, DPAK, or TO-220(F), DFN8x8 is a smaller package offering a well-balanced footprint and thermal dissipation. The 64mm² footprint makes AONV110A60 and AONV140A60 ideal for Active Bridge and high-density PFC/Flyback/LLC applications. In an internal benchmark, we compared 4 x AONV110A60 with the typical 8A GBU806 diode bridge under the 300W 90Vac scenario, the Active Bridge solution with AONV110A60 reduced the power loss by almost 50% (3.16W loss with Active Bridge vs. 6.12W loss with Diode Bridge) and increased the efficiency by 1.1%. The two DFN8x8 devices also find great fit in applications with only PFC and LLC stages, given 57% and 80% reduction in footprint and height, respectively, versus D2PAK.
Besides Server applications, AONV110A60 and AONV140A60 also target Solar Micro Inverter and Slim Adapter applications. Micro-Inverter design sees the trend of converting solar energy from two panels via one inverter, which means doubled power rating but not necessarily doubled the system size. DFN8x8 devices could help achieve this goal by paralleling and reducing effective Rdson, and accordingly, power losses. DFN8x8’s Kelvin Source would be much favored in a high Fsw inverter design, where switching losses are more significant and need to be minimized. In slim adapter designs, DFN8x8 devices, together with high Fsw controllers and planar transformers, could easily push the system density to 20W+/ in3 and efficiency up to 93%+ (with Active Bridges).
“Years ago, we could hardly imagine high voltage DFN8x8 devices widely adopted for server systems above 400W, even limited in low power SMPS, since people are used to through-hole or larger packages such as TO-220(F) or D2PAK. The power design concept has changed tremendously and rapidly with more and more DFN8x8 devices used in Active-Bridge, PFC, Half-Bridge, and Full-Bridge topologies. DFN8x8 devices’ value proposition is clear, it is a high voltage SMD package that offers smaller form factor, better switching performance (Low Eon), higher system reliability (Low Gate Ringing), and easier board assembly. AOS will continue to provide our customers with differentiated solutions that best serve the application needs and mission profiles from low power universal charging to high power server, solar, and telecom rectifiers,” said Richard Zhang, Director of High Voltage MOSFET Product Line at AOS.