Due to the semiconductor shortage in 2021 everyone realized that cars these days integrate a lot of electronics. The average number of computer chips per car has increased a lot in the last decade.
It is clear that the new applications require high-speed interconnects that are not possible with the initial, low-speed interface types. But there is also innovation possible for the old interface types like LIN/CAN by combining it together with other IP blocks on a single die.
For many years, IC designers coult count on the snapback behaviour of the ggNMOS device for ESD protection in mature CMOS nodes (180nm and below).
However, for more advanced CMOS, FinFET, SOI and high voltage processes there are serious drawbacks.
Some applications really need high voltage interfaces and circuits. Think about power management and power conversion chips, automotive electronics for engine control, LCD or OLED display driver chips, motor driver electronics and industrial applications. These high voltage applications require other ESD protection clamps compared to the clamps used for protection of low voltage circuits.
Sofics has been involved in a number of chip projects that require custom ESD clamps for high voltage interfaces.
Despite the fact that IEC 61000-4-2 is a standard created for system level ESD stress it is frequently used for stand alone integrated circuits. The test approach for chips is not defined nor standardized for this requirement so it is important to have a discussion on the test conditions and acceptance criteria. This article outlines 3 aspects that need to be considered if on-chip ESD protection needs to withstand the IEC 61000-4-2 stress