PIC's robustness to ESD?

[valemike]

I know the PIC has limited built-in overvoltage clamps. What do you guys use for ESD protection? Simple current-limiting resistors to each pin? Or do you guys find the need for external ESD protection ICs?

Thanks,
Mike

[newguy]

I typically err on the side of caution and always add external protection to any lines that leave the enlcosure or are used for user interface (buttons, etc.).

A nice 4 input esd array is the On Semiconductor MMQA6V2T1. Digikey carries it: MMQA6V2T1OSCT-ND. Really quite cheap at $.32 each (CDN) too.

To protect power & ground lines I usually use something like Littelfuse's SMBJxxCA transient voltage suppressors. They come in unidirectional and bidirectional versions, and work great at suppressing spikes. If you use one of the unidirectional versions across your power input, then it doubles as a polarity reversal protection device too.

I'd like to hear other people's opinions on this too. Like I said, I always err on the side of caution, but then again, esd hasn't been an issue for me either. Perhaps because of the protection, perhaps I'm just lucky.

[Ttelmah]

The PIC is pretty robust, but generally, I opto-couple everything!. However on simpler projects, I have used transorbs, plus pi filters, and systems with these have been in some cases running for over a decade, without failures.

Best Wishes

[valemike]

I recently implemented in the MAX6818 ESD protector/Switch Debouncer from Maxim.

For EMI + ESD protection, I have looked at ST's EMIF10* family, which has 10 EMI and ESD protection lines for just under a buck! Unfortunately, I need to buy it in quantities of 5000.

I've also looked into using transils (ESDA6V1S3).