21:33 <houkime> oh. here's another interesting ESD topic

21:33 <houkime> How susceptible caps are to esd damage.

21:34 <houkime> this is quite important for both SD and sim cards

21:34 <houkime> because they have powerfeed pins that need to be decoupled

21:34 <houkime> AND esd-protected at the same time!

21:36 <houkime> And as you can imagine both of esd and decouplers need to be as close as possible to the pin.

21:38 <houkime> So there's basically NO WAY you can protect these caps. They can't be far enough from esd interception point to be protected.

21:39 <houkime> because otherwise they will be useless as decouplers.

21:42 <houkime> So, how vulnerable are they? It seems like this depends to the large extent on their capacity, and anything uF-ish is ok and lesser caps are not really.

21:42 <houkime> *not really defended

21:49 <houkime> for SIM we have 1n caps and 220n caps. 220n is probably going to be ok. 1n may not.

21:50 <houkime> And I don't really have exact datasheets on caps models in use.

22:05 <Joerg-Neo900> >>In both JS-001-2012 and MIL-STD-883H the charged human body is modeled by a 100 pF capacitor and a 1500 ohm discharging resistance. During testing, the capacitor is fully charged to several kilovolts (2 kV, 4 kV, 6 kV and 8 kV are typical standard levels) and then discharged through the resistor connected in series to the device under test.<< I'd not worry much about capacitors

22:06 <Joerg-Neo900> IOW consider them immune to ESD

22:09 <Joerg-Neo900> then OTOH capacitor distance to contact point doesn't change by a relevant amount from placing the ESD as close to contact as possible

22:09 <Joerg-Neo900> and finally you often can place buffer caps on opposite surface of PCB

22:10 <Joerg-Neo900> particularly when you can have multiple vias to reduce their effective parasitic impedance

22:17 <houkime> ok.