600V power FETs that get “close to perfection”, says ST

August 27, 2015 // By Graham Prophet
With the assertion of switching performance that is approaching “perfect”, STMicroelectronics has extended its MDmesh M2 series of N-channel power MOSFETs with a family of devices that offer the highest power efficiencies in power supplies, especially under light-load conditions.

These 600V MDmesh M2 EP devices combine ST’s strip layout with an improved vertical structure and an optimised diffusion process to approach the ideal switch, with very low ON-resistance and the lowest available turn-off switching losses. They are tailored for very-high-frequency converters (switching frequencies of over 150 kHz), suiting them for the most demanding PSU applications.

Suitable for both hard- and soft-switching topologies, including resonant topologies such as LLC, these devices offer extremely low switching losses, especially under light-load conditions. In addition to the very low gate charge (Qg) – as low as 16 nC – exhibited by all MDmesh M2 devices, the M2 EP devices feature up to a 20% reduction in Eoff (turn-off energy), thus reducing by the same percentage the turn-off switching losses in hard-switching converters. This Eoff reduction in the low current range boosts the efficiency under light-load conditions, where efficiency-certification rules are becoming increasingly demanding. They feature an optimised capacitance profile for light-load conditions, and optimised Vth and Rg values for soft switching.

The enhanced shape of the turn-off waveforms leads to higher efficiency and lower noise in resonant converters, allowing more energy to be stored and re-used, rather than dissipated as heat, cycle by cycle.

In a range of packages (PowerFLAT 5x6 HV, DPAK, D2PAK, TO-220, TO-220FP, I2PAKFP, and TO-247) the MDmesh M2 EP family targets power-supply applications that require the highest efficiency levels. All devices are in full production, with pricing starting at $1.5 for the STD15N60M2-EP in a DPAK package (1000).

STMicroelectronics; www.st.com/mdmeshm2