Opto-CMOS

Oct 12, 2015 6 Replies

Can anyone recommend one of those optically isolated normally open analog switches, with a 250 volt breakdown voltage on the switch, that I can get my hands on real quick like? DIP package would be preferred if possible.


Ixys CPC1540. About 25 ohms on, pA leakage off, and will stand being across the AC power line, on or off.

Lots of capacitance of course.

Digikey has them.

I'm also wondering if an ordinary optotriac that I might have in stock would work for my application. I'm hoping to low-side switch some electroluminescent wire - it looks capacitive and the inverter frequency is about 2kHz and a hundred something volts P2P.

I don't know much about TRIACs so I dunno.

I found a couple MOC3010s still in their Archer Electronics blister packaging in my junk box. Date codes 8204. If I recall I spent most of

1982 babbling nonsense and being unable to read, write, or tie my own shoelaces, so we'll see how this works out

If one power rail of your logic could be common with one terminal of the EL inverter then you might be able to use an ordinary 450V NMOS (TO-92-like package e.g. ZVN0545A from Diodes iirc), with a DC-blocking capacitor in series with the FET drain (use a capacitance value several times higher than the EL wire capacitance), so that the inherent diode of the MOSFET does not cause any problem when in the off-state. The FET needs to have a VDS rating of at least the peak to peak swing out of the EL inverter. Probably you could use a bipolar instead of a MOSFET too, e.g. MPSA42 if it is cheaper, though some reverse current might flow initially in the C-B diode - probably not a problem.

Chris

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