[gta02-core] SD/SIM vs. ESD and EMI

Patryk Benderz Patryk.Benderz at esp.pl
Tue Dec 1 15:13:37 CET 2009

Dnia 2009-12-01, wto o godzinie 09:59 -0300, Werner Almesberger pisze:
> Patryk Benderz wrote:
> > but i believe that it is wise to
> > design PCB in a way, that you can apply fixes later - as history of
> > GTA-02 teaches us ;)
> Heh, definitely :-)
> The issue here is that gta02-core (like GTA02) doesn't have ESD
> protection on the SD/SIM holder. This is against the book, but I
> think we got away with it because one will almost certainly touch
> one of the grounded metal covers before reaching the SD or SIM
> contacts, and thus be free from any electrostatic charge.
great, after this paaragraph i understood what ESD is :)
(Electro Static Discharge ?)

> Of course, we shouldn't rely on such things. So my question is
> if the electrical properties of a TVS (transient voltage
> suppressor) are such that we could put TSVs in lieu of the
> capacitors that we already have on those lines, in case we want
> to improve the ESD protection.
> If this is at least theoretically feasible, then we don't have
> to worry about the issue for now and are thus one step closer to
> finishing the schematics.
> (The question actually goes beyond this, because if a TVS acts
> like a regular capacitor, then it would be even wrong to just
> put a TVS in parallel to a capacitor without adjusting the
> capacitor's value accordingly.)
Definitively I am not an expert here (rather newbie), but wouldn't
Zener's diode be sufficient to take this electric charges to GND?

Patryk "LeadMan" Benderz
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