FR-4-Properties-Custom Design Circuit Board Electronic Pcb​

- Dec 31, 2016-

FR-4-Properties-Custom Design Circuit Board

Electronic Pcb


Typical physical and electrical properties of FR-4 are as follows. The abbreviations LW (lengthwise, warp yarn direction) and CW (crosswise, fill yarn direction) refer to the conventional perpendicular fiber orientations in the XY plane of the board (in-plane). In terms of Cartesian coordinates, lengthwise is along the x-axis, crosswise is along the y-axis, and the z-axis is referred to as the through-plane direction. Keep in mind that the values for the parameters listed below are an example for a certain manufacturer's material. Each manufacturer will have slightly different values for the parameters listed below. It's better to check the datasheet of the specific material being used. Verifying the actual values is very important for high frequency designs.

Specific gravity/density1.850 g/cm3 (3,118 lb/cu yd)
Water absorption−0.125 in < 0.10%
Temperature index140 °C (284 °F)
Thermal conductivity, through-plane0.29 W/(m·K),[1] 0.343 W/(m·K)[2]
Thermal conductivity, in-plane0.81 W/(m·K),[1] 1.059 W/(m·K)[2]
Rockwell hardness110 M scale
Bond strength> 1,000 kg (2,200 lb)
Flexural strength (A; 0.125 in) - LW> 415 MPa (60,200 psi)
Flexural strength (A; 0.125 in) - CW> 345 MPa (50,000 psi)
Dielectric breakdown (A)> 50 kV
Dielectric breakdown (D48/50)> 50 kV
Dielectric strength20 MV/m
Relative permittivity (A)4.4
Relative permittivity (D24/23)4.4
Dissipation factor (A)0.017
Dissipation factor (D24/23)0.018
Dielectric constant permittivity4.70 max., 4.35 @ 500 MHz4.34 @ 1 GHz
Glass transition temperatureCan vary, but is over 120 °C
Young's modulus - LW3.5×106 psi (24 GPa)
Young's modulus - CW3.0×106 psi (21 GPa)
Coefficient of thermal expansion - x-axis1.4×105 K−1
Coefficient of thermal expansion - y-axis1.2×105 K−1
Coefficient of thermal expansion - z-axis7.0×105 K−1
Poisson's ratio - LW0.136
Poisson's ratio - CW0.118
LW sound speed3602 m/s
SW sound speed3369 m/s
LW Acoustic impedance6.64 MRayl

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