In electronics, ESD is a very high voltage (generally >500V) and moderate peak current (~1A to 10A) that occurs in a short time frame (generally <1µs). It comes into play when two conductive objects approach each other and form a strong electric field, which can cause a field-induced breakdown. An arc can occur when the voltage between the objects exceeds the breakdown voltage of the air and the insulation between them. In environments where the relative humidity is very low, an ESD event may have a peak voltage as high as 15,000 volts. The arc continues until the objects touch, shorting out the arc, or until the current drops too low to sustain the arc.
ESD can occur throughout a product’s manufacturing, testing, shipping, handling processes, or during field service operations. It can result from a discharge to the device, from the device, or from induction to the item from an electromagnetic field.
If the ESD pulse finds its way into an electronic device, the circuitry inside can be physically damaged. The current injected by the arc can break through the thin insulating layers inside components, damaging the gates of MOSFETs and CMOS devices. It can also trigger latch-up in CMOS devices and short-circuit reverse-biased PN junctions
Engineers often fail to account for ESD until product release is imminent, requiring them to make expensive last-minute fixes or completely revamp the product design. The cost of repairing an ESD-damaged electronic device can range from a few cents to hundreds of dollars, according to the EOS/ESD Association. When combined with its other costs, including lost production time, shipping, and labor, the cost impact of ESD can be quite significant.