[gta02-core] ECN0032 (EMI and ESD protection for headset jack)

Werner Almesberger werner at openmoko.org
Wed Oct 7 03:04:09 CEST 2009

Rene, we discussed using a single filter component instead of a discrete
"pi" configuration. What's your opinion ? I'm a bit concerned that we
may end up with a lot of components to place in this already crowded
area, and risk getting unexpected secondary effects.

Also, do we still need C4405 ? If I understand things correctly, it just
stands guard against general EMI badness, but since we have a real filter
now, it can only make things worse, no ? ECN0032 mentions its removal,
but the schematic still has it.

R4401 is for general DC protection ?

By the way, if we replace the pis with integrated filters, we should
have enough room to draw the various stages such that they don't
overlap, i.e., one (virtual) rectangle with the jack, one with all the
TVSs, one with all the filters, and then all the rest, including the
branch JACK_INSERT branch. That should make the whole affair look a bit
less intimidating.

- Werner

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