Alpha and Omega Semiconductor releases high voltage MOSFETs

Alpha and Omega Semiconductor have 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, that’s been designed to meet the high efficiency and high-density needs for Quick Charger, Adapter, PC Power, Server, Industrial Power, Telecom, and Hyperscale Datacentre applications.

Server Power designs are being 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, 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, 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 suitable for Active Bridge and high-density PFC/Flyback/LLC applications. 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, these devices are also suitable for 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 favoured in a high Fsw inverter design, where switching losses are more significant and need to be minimised.

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).

Technical Highlights

  • Low Ohmic devices packaged in 64mm² DFN8x8
  • Package Thickness < 1mm
  • Kelvin Source and Low Eon/Gate Oscillation
  • Automated SMT assembly
  • MSL Level 1