PCB FR4: Which Material is Right for Your Project?

Circuit Board FR4

Wondering which FR4 your PCB needs? Today we dive into this common circuit board material is and which one you will need to specify in order to make your project a success.

What is FR4?

FR4 is the NEMA (National Electrical Manufacturers Association) designation for Flame-Retardant fiberglass reinforced epoxy material. This material makes it so your circuit board is protected from heat when soldering as well as other elements. A standard FR4 PCB will have a layer of FR4 sandwiched between two thin layers of laminated copper. Note that FR4 is not a material but is a designation by NEMA. However it is often referred to as a material.

Differences between PCB FR4 Materials

You will have to specify a few things for your board. First, is its glass transition (TG). TG can range from 115°C to 200°C for the High TGs (HiTGs) depending on the manufacturing methods and the resins used. Generally Standard FR4 is okay for leaded soldering which uses temperatures with it heat resistance range of 140°C to 150°C. Lead-free solder (RoHS) requires a higher melting point so High TG FR4 will need to be specified. High TG FR4 has a heat resistance of around 180°C. High TG also has better resistance to moisture and other elements. We have found that in general, High TG will increase a boards cost by about 5%. These are the two most popular FR4s however there is High CTI FR4 and others used in high frequency/high voltage situations.

FR4 has other specifications that you can see in this Data Sheet put together by electronics component supplier Farnell: Data Sheet for FR4

More Questions?

Vinatronic has the expertise to guide you through your bare board procurement. We have relationships with fabrication shops all over the world and have the capability to pair you with the factory most suited for your project. If bare boards are purchased in conjunction with assembly, we will be sure to get you a discount.

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