@User For those of us using the io_analog pads would you recommend creating our own 'primary' esd (similar to what is included by default in caravel for the other gpios) in addition to the 'secondary' esd discussed a few weeks ago?

Yes, everything you say applies. You can follow or clone the ESD design by John Kustin.

Great, thanks for your response. I'll clone that for my secondary ESD circuitry, but mine will be a bit more complicated needing separate primary esd and clamp. (I assume I can clone Kustin's secondary esd for my primary as well. - following the slides from the meetup on the topic) & I'll dig into the pdk a bit and see if I can find the power clamp circuitry they use. Can I send you what I put together as a sanity check I've done it correctly?

Sure.

Great, thanks.

Hello @User @User. I saw in the Sky130 documentation that there is a primary ESD available and for the I/Os that are going to be used as analog we need to add one more ESD (secondary ESD) to bring down the voltage further. So what about the digital I/O's ? Will Openlane lay the secondary ESD or is that not required? Is my understanding about ESD right? Thank you in advance.

If you are using GPIO for digital, there is nothing you need to add. You just need to add the secondary ESD when you tap the pad directly for analog usage. The digital path is inherently fully protected inside the pad cell (nothing to do with OpenLane).

Ok thank you Prof.Murmann for the reply.