On Tue, Feb 25, 2025 at 06:16 PM, Corey KC9RAV wrote:
assembling a QRP labs kit doesn’t require ESD protection. It doesn’t hurt, but there isn’t any major ESD risk.?
And that is why some people have failures in their assembly, or after operating for a time (due to a weakened part).
There is indeed ESD risk.
Yes, the ESD risk is minimized since most of the parts have ESD protection on their input pins, and are pre-assembled onto the CCA.?
And the risk is not as critical (like Jerry mentioned) since we are hobbyists, not making mission critical gear - and we can easily fix it if it breaks.
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But the highly integrated parts in the Q*X with fine internal lithograpy (all of the ICs except the 3.3V regulator) can indeed be damaged with careless handling.?? ESD may not cause failure immediately, but may weaken a part that may then fail later.? Yes, even with the ESD protection on their pins - it just takes a larger ESD event.? The pins are typically ESD protected to 2000V, which protects well if handled carefully.? But picking up a styrofoam coffee cup from your work table and brushing it against the cuff of your shirt can generate well over 20,000 volts of static on your hands - then touching one of those devices without discharging yourself will indeed damage it.? Thankfully most of us don't use styrofoam on or near our work surfaces, but many other materials, including carpeting, the covering on your chair, your chair's roller wheels, and even your clothing can readily generate high static charges, unless these materials are of the anti-static variety.? And how many of us have checked??
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Sorry for the tirade, but I had to take ESD refresher training every 6 mo during much of my career.? And it was interesting to learn of the common materials and simple body movements that can generate static tens of times greater than the typical 2000V ESD protected device can withstand.? So unless you know you are safe, use an ESD mat and ground yourself after moving or wear a wrist strap.? Assembly areas where I worked have chairs and floors that are known not to generate static.? And we still had to wear our wrist bands or shoe straps, and work on ESD mats that were tested and qualified every 3 mo.? Yes we worked on mission critical devices, and we had to avoid all ESD risk, unlike hobbyists.?
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After the item is assembled, the risk is lower, because there are many paths to dissipate ESD, and you usually don't directly touch an ESD sensitive device without previously discharging the ESD through a benign path.? And maybe that's why we don't often kill the ICs in qrp-labs kits.
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But please don't believe that there isn't any ESD risk unless you are specifically minimizing it in some way.
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Stan KC7XE
