[sdiy] Does Source = Drain???

[Ian Fritz]

At 03:59 AM 6/13/2010, Antti Huovilainen wrote:

>Are there some common MOSFETs that are truly symmetrical?
>Those would be useful as switches since they lack the parasitic diode of 
>JFETs.

I looked for this a couple of years ago and didn't find anything.

My through-zero Saw VCO requires discharging both positive and negative 
ramps.  For this bipolar operation I use two MOSFETs in series so that only 
one protection diode is turned on at any time. This is the standard 
solution as far I have seen.  You increase the parasitic capacitances when 
you do this, but a small-signal MOSFET like the VN0106 has quite small 
capacitances and works well.

Ian





>Antti
>
>"No boom today. Boom tomorrow. There's always a boom tomorrow"
>   -- Lt. Cmdr. Ivanova
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