AOS releases two super junction MOSFETs in slim DFN packages
Two super junction MOSFETs in DFN 8.0 x 8.0mm packages, the 600V 110mOhm and 140mOhm αMOS5 devices have been optimised for low profile server power, PV micro inverters and slim adapters by Alpha and Omega Semiconductor (AOS).
The 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, telecomms and hyperscale data centre applications.
The AONV110A60 and AONV140A60 are two 600V low Ohmic MOSFETs packaged in the 8.0 x 8.0 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 balanced footprint and thermal dissipation. The 64mm² footprint makes the AONV110A60 and AONV140A60 suitable for active bridge and high-density PFC / flyback / LLC applications. An internal benchmark compared four AONV110A60 MOSFETs with the typical 8A GBU806 diode bridge under the 300W 90V AC. The active bridge solution with AONV110A60 reduced the power loss by almost 50 per cent (3.16W loss with active bridge versus 6.12W loss with diode bridge) and increased the efficiency by 1.1 per cent, reported AOS. In applications with only PFC and LLC stages, the two DFN8x8 devices also showed 57 per cent and 80 per cent reduction in footprint and height, respectively, versus D2PAK.
AOS explained that 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 reduced, designers have to choose components with lower losses and small dimensions. Given the large stray inductance (larger Eon losses) and unsuitable height of traditional through-hole package, these types are no longer viable 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 minimising magnetic and switching losses by leveraging ZVS/ZCS topologies, designers are increasingly replacing the diode bridge with high voltage MOSFETs, which serves as an active bridge rectifier through the control of a driver (for example AOS’s AOZ7200).
In addition to server applications, the 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 Rds(on), and accordingly, power losses. DFN8x8’s Kelvin source would be much favoured in a high Fsw inverter design, where switching losses are more significant and need to be minimised, advised AOS. In slim adapter designs, DFN8x8 devices, together with high Fsw controllers and planar transformers, could increase system density to 20W+/ in3 and efficiency up to 93 per cent (with active bridges).
The AONV110A60 (600V 110mOhm DFN8x8) and AONV140A60 (600V 140mOhm DFN8x8) are immediately available in production quantities with a lead-time of 24 weeks.
