There are lots of design functions which are critical yet underappreciated, and ESD protection is one of them. While a snappy GUI, high-resolution display with fast graphics, or sophisticated algorithm may get some kudos, a diligent job at ESD, transient, and overvoltage protection is unnoticed unless you don't do it, or don’t do it right.
This protection can take many forms, depending on the product and application, of course. A device with external I/O lines, such as a telephone-line interface, may need protection against lightning, accidental connection to an AC line, or induced transients. In contrast, a wireless handset with touch screen may need protection primarily from static-electricity forms of ESD.
So how to you meet the protection challenge? Some ICs provide some level of protection, using internal diodes. These may work, up to a certain limit. But often, you'll need external, discrete solutions, such as specialized clamping devices, PTC components, or even gas-discharge tubes (have you ever seen these in action? Very impressive, indeed!). And those are just a few of your options.
Problem is, of course, that the external discrete devices add to your BOM, cost, and PCB footprint requirements. Sometimes, it's tough to convince the design-review team that the hassle is worth it. But you cab sure if you don't add them in as needed, you'll get call when there's a problem&8211;and maybe even the blame.♦