gigAtec SA

PCBs: the choice is yours

August 2023

By habit, we sometimes tend to choose a standard PCB, i.e. an FR4, without questioning this choice.
Here, we'll take a look at the main options available to us, as the extra costs are sometimes not as great as we might have imagined.

FR-4

It's a fiberglass-reinforced epoxy resin composite. It is therefore rigid, low-flammability (FR -> Flame Retardant ) and inexpensive.
As standard, it has a heat resistance of at least 140°C. In the High Tg (Glassy transition) version, its resistance rises to 180°C.
Although the most commonly used thickness is 1.6mm, versions as thin as 0.2mm (at the expense of rigidity and heat resistance) or thicker (2.36mm) are also possible.
Commonly made in green color, FR-4 PCBs are available in other variants (red, blue, black, white), usually at no extra cost.

Polyamid

This polymer offers excellent flexibility and is highly resistant to traction and torsion. It is therefore ideal for making flex-rigid PCBs.
It is widely used in the aerospace and defense industries.

PTFE

This ceramic material is ideal for high-frequency applications, thanks to its well-controlled impedance. It is often referred to as Rogers, the name of the company based in Arizona (USA) which manufactures the ceramics used by PCB manufacturers. This material, available in several versions, degasses very little and is readily used in space applications.

CEM-3

Easily recognized by its slightly milky white color, CEM3 offers good thermal dissipation and is suitable for single- and double-sided PCBs only. This makes it ideal for LED lighting boards and some power applications.

Metal

The most commonly used metal is aluminum in the following configuration: aluminum, dielectric and laminated copper layer.
Its high heat dissipation and rigidity make it a popular choice for power applications.