Feature: Components


These were specialised lateral MOSFETs, comparable in design but with less thermally-related distortion


Te range offered high linearity, slew rate and voltage capability,


and resistance to secondary breakdown and thermal runaway. Lateral MOSFETs shot to fame in the ‘70s and ‘80s when


Hitachi first released its 2SJ50/2SK135 and 2SK176/2SJ56 devices. Developed especially for linear audio amplification, they earned a legendary status in the audio industry and became much coveted components; however, Hitachi ended their production. In 1993, Profusion followed this up by introducing the


Exicon brand: specialised lateral MOSFETs, comparable in design but with less thermally-related distortion. For the past ten years, Exicon has been the only maker of


TO3 lateral MOSFETS, which continued to be a staple part for designers of high-power analogue amplifiers. The list of amp manufacturers that used these devices


The end of the (production) line for the lateral MOSFET By Profusion technical staff


P


rofusion’s lateral MOSFET brand Exicon had stopped producing its longstanding metal-can MOSFETs. These widely-respected components have been in production for some 30 years, playing a fundamental role in many professional audio and DIY amplifier designs.


An outstanding part Exicon has made lateral MOSFETs since 1993, with several refinements added over the years.


30 September 2022 www.electronicsworld.co.uk


is very long: Aguilar, Ashly, Audio by Van Alstine, Chevin Research, Classé Audio, Goldmund, Hafler, HH, Hughes and Kettner, Laney, Mesa Boogie, MTX SCS, Nagra, Soundcraftsmen, Trace Elliot, Vestax, among others. Exicon MOSFETs have also long been a foundation of


the DIY amplifier community, where their high speed and exceptional sonic characteristics made them first choice of even the most scrupulous audio enthusiasts. They became the first choice for John Linsley-Hood, revered


developer of the simple Class-A amplifier, and have since been proposed for numerous revisions and amp designs in the pages of Electronics World. Inspired by their use in high-quality amps by Swiss manufac-


turers such as Nagra and Goldmund, contemporary audio designers including Soo In Chae of the Korean manufacturer Bakoon, have praised the lateral MOSFETs’ outstanding properties, “with indeed exceptional quality of sound”. HiFi.nl recently stated that Exicon “belongs to the ‘cream of the crop’ in the field of FET audio components”.


New parts However, more recently due to a significant increase in manufacturing costs and a gradual decline in demand, Profusion decided to cease the production of these MOSFETs. In May this year, the company issued an end-of-life (EOL) notice for the longstanding metal-can versions of its Exicon line of lateral MOSFETs. Exicon’s two plastic lateral MOSFET versions, the TO247


and TO264, remain active and available for new designs; more details can be found at profusionplc.com and exicon.info.


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