Modern electronics. Do we still need to be careful about ESD?

I am very sloppy with ESR protection, except when handling discrete mosfets.

I seem to get away with it.

I've never worked about ESD and never had a problem. However, I believe it can depend on a lot of things such as humidity. We have a trampoline on the garden that seems to generate quite a charge. Maybe I should test what happens with a cheap IC?

ESD precautions take many forms, whether they are needed or not depends on the work being done, the susceptibility of unconnected inputs and outputs, the earthing of electric tools (e.g. soldering irons) and instruments (e.g. oscilloscopes), the nature of the item being worked on (e.g. Xenon flash guns, electronic ignition systems, electric fence generators, lightning conductors, etc). A basic rule is that anything with very sensitive unterminated inputs is likely to be damaged by ESD and therefore precautions should be taken. This includes individual semiconductor devices that are straight out of the packaging and have yet to be installed. When assembling a PCB I usually leave such devices to the last.

ESD can come from devices being worked on too, e.g. switched-mode PSU's, ancient TV sets, etc. The discharge can flow into whoever is doing the work, causing him or her to drop or throw away the item whereupon various bits of it will probably break. It can be argued that wearing an ESD strap under such circumstances can actually make things worse.

In my opinion the best ESD protections of all are to know what you are working with, read the manufacturers specifications if in any doubt, stand on a rubber mat, make sure everything is earthed that should be earthed, don't touch any unconnected terminals on ICs or discrete semiconductor devices, and try to deal with unexpected consequences before they happen.

Despite all this, I once gave myself quite a strong electric shock simply by testing the low voltage side of a small mains transformer for continuity. The transformer was not connected to anything and I was holding it in my hand, manipulating the probes of an analogue multi-meter with my other hand. When I disconnected the meter the sudden interruption of the current in the low voltage winding generated a large voltage at the terminals of the high voltage winding. Good job the current only flowed across the palm of my hand!

Hi Dale,

I have a copper strip that runs the front edge of all my work tables. The strip is tied to Earth ground through a 10K resistor. As I sit at the bench and work my forearms are frequently in touch with the strip. I try to be extra conscious when I am dealing with potentially sensitive parts and boards. The fact is that you only need to be careful with the semiconductor components that you want to work properly. For me this is all of them. You will never regret being too careful.

John

Hi Dale,

It also depends on the context, to determine the amount of attention that is needed.

If you're prototyping then you can get away without much care. If ESD damage occurs you can troubleshoot or replace the part, and probably you're taking some precautions without realising it, just out of habit, like not moving as much while assembling parts, not touching the legs of parts if possible, etc. Running up or down the stairs and then immediately handling a MOSFET is probably not a good idea though!

In production it's a totally different story for good reason. Any slight failure rate will result in significant failure quantity over time, and it could manifest in the field later too. Then it's another problem to deal with all the issues caused to the customer. I had a full-time job once just trying to figure out if field failures were due to production issues or not, such as bad ESD practice or faulty machines knocking parts etc.

Personally for prototyping I do the same thing as mentioned above, regarding soldering down all passives first if possible, so that the semiconductors have a bit more protection. Some (perhaps older) circuit topologies used very sensitive parts, like particular MOSFETs that came with wires shorted together to be remove after soldering.

Anyway, long story short, for prototyping you may find practically that some ESD practices can be reduced with little noticeable effect, given that some steps are mentally performed to minimise the risk anyway. Personally though I still take care to store parts well, use conductive mat, at least regularly touch the metal conductive part of the iron (a cold part of it obviously!), don't move around too much, don't have loads of layers of clothes on, not touch metal parts of components when placing them with tweezers, use ESD tweezers and so on. They are all small easy things to do.

ESD is still a big deal in electronic assembly areas.

Most electronic components today have some level of ESD protection built-in, but it always has its limits. It would take a large volume to describe all the in and outs of ESD issues and protection methods.

I don't wear a ground strap, but I have a whole list of things I do automatically that reduce the risk of ESD damage.

Including wearing real cotton clothing, no carpets, keeping my body and fingers away from sensitive components, and touching a ground before handling risky components. I don't even think about it, I just automatically do or don't do a bunch of things. It isn't an ideal process, and I'm not actually a fan of excessive ESD precautions, this is just what I do.

ESD does cross my mind when I see someone wearing a wool sweater grab sensitive circuitry - it makes me cringe.

ESD damage is certainly real - and almost all modern components are susceptible in some way or other.

How much of a problem it is depends on a great many local factors.

Where I live (SW Scotland, cool and damp) and where I work (fairly damp factory unit) mould is a bigger problem than ESD !

Very occasionally in winter it can get dry enough to get static sparks from touching earthed things - these sparks can damage pretty much anything that isn't protected.

If you are producing electronics in volume or for sale it's best to err on the safe side and take reasonable precautions (mats, wrist or heel bands, static charge checking of assembly areas etc).

The really sneaky thing about static damage is that it may not kill components quite dead but may affect reliability or performance.

I work on a conductive mat (which is grounded) but I don't wear a wrist band.

MK

First I would like to thank everyone that commented on my question.

Going over each response, I found Doug's answer to be in-line with my training and work habits. 

I have worked with many different companies over the last 40 years. Like to mention two companies that provided excellent hands-on training. Apple and Hewlett-Packard.  I worked with a few Apple authorized corporate integrators from 1984 to the late '90s Then I had the opportunity to join an HP Office product Government supplier and System integrator.

The main reasons that I bring up ESD today are simple, the more I talk about in different forums younger Makers get the opportunity to understand the reasons why it's important to understand how harmful even the smallest electrostatic discharge can damage delicate electronic components. Most of you that responded to my question understand ESD and the problems it brings. The MAKER community is expanding at a higher rate than I have seen in many years. A lot of younger people are you getting into electronics without the opportunity of proper education due to the lack of funding. I feel that the older generation of MAKERS should pass along as much information as we can whenever possible.

Thanks for taking part in my question, I'm very encouraged by the responses I received. 

Dale Marcell

Stay safe and healthy.

Footnote:

I have always found the resources provided by elements14 to be extremely helpful in my research.

There is one guide called ( ESD/EMI protection for your new design.)  Created by ssilberhorn  and published in 2012)

Do a search on this title if you are interested in learning more ESD protocols