touch-based control

uvknhn · Joined: Apr 14, 2022 Posts: 1 Location: iowa

How can I protect CMOS chips from ESD for a touch based interface? Is diodes and a resistor enough?

okelk · Joined: May 08, 2014 Posts: 71 Location: Vienna

most cmos ic's have internal clipping diode, they just can't handle a lot of current....In my experience just adding a 1k resistor is fine. (but i guess i would'nt do it like that if I would sell a product.) but of course there'nothing wrong with adding some clipping diodes if you want to be on the safe side.

for simple touch switches to interface with logic chips i used simple darlington transistors before ( two of any npn transistor or a single bc517 )
like the first circuit on this page:
http://talkingelectronics.com/projects/TouchSwitch/TouchSwitch-1.html