Methods To Protect PCB From ESD Damage

Here we will prove that analog parts with larger geometries are most suitable for protecting field programmable gate arrays (FPGAs) with their smaller geometries.

Large steel structures, cars, mountains, and even people can survive real atmospheric lightning. Humans can also create their own miniature lightning (sparks) and survive. However, when these sparks reach the IC, they can cause major failures.Nano-scale transistors need to be protected so that they can be spared even under human sparks.

Microprocessors have been increasing the density of digital semiconductors for a long time. Manufacturing technology has led to smaller and smaller transistors. In 1971, the Intel® 4004 computer processing unit (CPU) was introduced with a geometric size of 10 µm. In the 1980s and 1990s, this process made the volume of the part smaller than the volume of the bacteria. In 2012, the density of ICs was 1,000 times smaller than the technology in 1971, and the functions on the chip were smaller than viruses. In 2012, people can buy a 28 nm-capable FPGA and 6.8 billion transistor packages, and the density is expected to double in the next few years. Small transistors are tightly packed together and need to operate at low voltages (usually 1 V and below) to control the heat generated.

To see through 28 nm, pay attention to zero: it is one 2.8 billionth of a meter (0.000000028). Let the distance between San Francisco and New York City represent one meter (about 4000 kilometers or 2500 miles). 28 nautical miles (one of 36 million parts) is now 0.11 meters or 4.4 inches. How much lightning must a device of such a small geometric size be damaged by lightning? How to protect this necessary and useful FPGA?

The simple answer is to use I/O interface devices that bridge the digital and analog worlds. The geometric dimensions of analog mixed-signal ICs are relatively large (10 to 100 times larger than digital integrated circuits) and have a higher voltage (usually 20 V to 80 V or higher), which makes them more robust than miniature digital transistors .