What’s FR-5 Laminate in PCB?

 

FR-5 (or FR5) is a glass fabric reinforcement in a high temperature epoxy resin binder in PCB base materials, like CCL. FR5 is a fire-retardant grade of G11. The natural color of FR5 laminate is typically yellow green-tan blend. It maintains good properties at both dry and humid conditions. It certifies to NEMA FR5. CTE of FR5 laminate in the xy plane is approximately 14 ppm/XC (25XC to 130XC).

 

Features

 

  • The coefficient of thermal expansion (CTE)  of epoxy resin in the z axis is approximately 4% at a range of 50XC to 288XC.
  • The glass transition temperature (Tg) of FR5 is typically between 170-180oC. Continuous operating temperature for FR5 is typically 140 oC. High Tg laminate is best suitable for multilayer PCB with higher layer count.
  • Higher operating temperature and superior mechanical properties at elevated temperatures.

 

FR-5 PCB Benefits

  • Extremely high mechanical strength at elevated temperatures
  • Good dielectric loss
  • Good electric strength in dry and humid conditions
  • Good chemical resistance
  • Low moisture absorption

FR-5  is a thermosetting fiberglass composite. It is a great option for multilayer PCB designs. It has excellent mechanical properties at high temperatures and performs exceptionally well during the lead free PCB assembly process. It has a low dielectric loss and high chemical resistance with almost zero moisture absorption.

Automotive producers also considered FR5 glass epoxy laminate to be the best material due to its improved Tg for automotive applications. It is well known for its high-temperature applications. FR-5 PCBs are often found in Antenna Isolators, Circuit board holders and Test boards, and Solder Frame applications.

 

FR-5 vs. FR-4

FR-5 has a better advantages than FR-4:

  • Tg, Td higher
  • Heat resistance is better, about twice the normal FR-4
  • Z-CTE smaller, suitable for high multi-layer board
  • T288 better

FR4 and FR5 epoxy board by a special electronic cloth impregnated with epoxy phenolic resin and other materials by high temperature and high pressure hot plate made of laminated products.