Author Topic: TVS diode with weak pullup - is leakage current a problem?  (Read 4231 times)

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Offline T3sl4co1l

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Re: TVS diode with weak pullup - is leakage current a problem?
« Reply #25 on: March 27, 2021, 06:01:27 pm »
It lacks filtering.  Adequate debouncing can be done digitally so it isn't a huge deal.  It will fail in the presence of more than a few volts of RF.  Not great, not terrible.

Y'know, phono jacks are probably quite insensitive to charged cable transients -- that is, say a cable ends up with a charge between conductors, due to odd fields around the connector, handling (triboelectricity between the wires in the cable), etc.  Even if you insert it carefully, it'll be impossible to avoid shorting it out, or at least approaching a gap that can be bridged by more than a few kV.  The hundreds of volts left over will be easily handled by the ESD diode.

Tim
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Offline SaimounTopic starter

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Re: TVS diode with weak pullup - is leakage current a problem?
« Reply #26 on: March 28, 2021, 08:29:06 am »
Hi Tim

The debouncing is done digitally indeed. I originally had a small RC filter but I removed it when I saw the digital debouncing was enough.

Good point about RF interference, I'll do some tests with my phone on a call right next to the board - unless someone has a better idea? :)

And yes I agree about the jack, you almost always short Tip to Sleeve (=GND) when you insert it. But as I said above I imagined a scenario where the cable is already plugged in, but someone/something with a charge touches the tip of the cable then that would go straight through the ESD diode and the series resistor.
 


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