ESD on GPIO/UART?

Timothy D. Swieter

I'm designing a modules that has power (+5V or +3.3V and GND) and a couple I/Os, basically a UART interface with RX, TX, RTS, CTS and status pins (logic voltage of all these pins are 5V or 3.3V). I'd like to ensure this module is robust and so I'm exploring putting ESD on them. Typically I've not seen ESD implementing on breakout boards sold at Parallax, Sparkfun, Adafruit, however this module may appeal more to industrial or commercial customers and so I thought adding ESD would help in those environments.

What do you think, add ESD? Skip it? If adding ESD, any parts/practice you recommend?

During development I could see this module getting plugged/unplugged. Once deployed it would stay plugged in.

Thank you.

kwinn

Clamping diodes and resistors on the I/O lines might be worth while, as would mov's on the power input but I rarely go beyond that unless there are power line noise issues.

geo_leeman

Something like these on the IO lines does a good job I think.

jmg

Timothy D. Swieter wrote: »

... Typically I've not seen ESD implementing on breakout boards sold at Parallax, Sparkfun, Adafruit, however this module may appeal more to industrial or commercial customers and so I thought adding ESD would help in those environments.

What do you think, add ESD? Skip it? If adding ESD, any parts/practice you recommend?

ESD is common on USB connectors, and those ESD parts have good volumes behind them, to keep the prices down.
Which part are you using, does that part already have an ESD rating ?

Timothy D. Swieter

The items I'm putting on this breakout board is a bit of a black box right now. I'm going through NDA process to learn more. The analogy though is to think of it like a GPS module with a UART interface.

I've not picked out parts. I'm open to suggestions. Thank you so far for the comments.

kwinn

Comm driver chips have pretty good esd protection but if the environment is really harsh you may want to consider optoisolators. That was the only thing that would work reliably around the arc furnace and other equipment at one location where ground voltage differences could be as high as 60VAC.