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SiC Schottky Diode to make SP2T switch?

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ge

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dick_freebird

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You want high Cj for the "On" state. Question is,
how far can you swing it for the "off" state isolation.
That's the big deal for PIN diodes, the thick "I" region
gives you the low Cj with large reverse bias.

Shottkies won't however give you the large diffusion
capacitance that a forward-biased PN or PIN would.
There are no minority carriers to do that. So your
"on" C will just be junction area without the
conductivity and capacitance modulation, with
a Schottky. The capacitance range (on-off) is
what you work with. If you can find C-V curves
then you could make that call, Cmax/Cmin is
roughly the isolation / insertion loss ratio (though
this will not be dB / log form as those are usually
expressed, I'm sure you can do the arithmetic).
 
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ge

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Understand what you are saying Freebird and thanks. This will take more research to find C-V curves for SiC diodes.
For some reason there is extremely few SiC PiN diodes but plenty of SiC Schottky diodes on the market. I'm digging through internet to find out why there is so few SiC PINs before I go further on SiC Schottkeys. Initial research makes me think it is either cost or poor yields of SiC PiN diodes.

I have to take my shoes off to convert between linear and log/dBs.
Thanks again.
 

Easy peasy

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The better types of SiC diodes for power electronics are PiN types - they handle over current much better but have dv/dt limitations esp at low temps ...
 
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ge

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vfone

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One of the most important property of an RF switch is "isolation", which mainly is given by Ct capacitance, which is: total capacitance at zero or reverse bias.
A PIN diode used as an RF switch have Ct capacitance less than about 0.5pF (even 0.1pF), and can be used as an RF Switch from about 100MHz to about 50GHz.
A Schottky diode designed to be an RF detector have Ct less than about 2pF, when Schottky diodes used as power rectifiers have capacitance few hundreds of pF.
A Schottky diode designed to be an RF detector, could be used as an RF switch, with some isolation and frequency limitations.
 

    tony_lth

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