SMT PCB Assembly FAQ
Some of the substrate materials used in high voltage PCBs include: BT epoxy, phenolic cured rigid laminate, high voltage Teflon (HVPF).
Maintain clearance between high voltage drop traces. Avoid any sharp turns and edges as they can act as areas for concentrated electric fields. Avoid running very high voltage traces on the inner layers of the board.
RF boards have many different applications, including wireless technology, smartphones, sensors, robotics, and security.
Generally, any circuit board that operates above 100MHz is considered an RF printed circuit board.
The high-frequency material most familiar to users of PCB laminates is probably polytetrafluoroethylene (PTFE), a synthetic thermoplastic fluoropolymer with excellent dielectric properties at microwave frequencies.
FR4 is the most used material in PCB construction. Circuit boards made of FR4 are strong, waterproof, and provide good insulation between copper layers, minimizing interference and supporting good signal integrity.
FR4 is a type of printed circuit board substrate made of flame retardant epoxy resin and glass cloth.
The standard thickness of the PCB is 1.57 mm. Some manufacturers will accommodate other specific thicknesses of 0.78mm or 2.36mm. When we say "thick" or "thin" FR4, we are usually comparing to the standard thickness of 1.57mm.
FR4 is the standard defined by NEMA (National Electrical Manufacturers Association) for glass-reinforced epoxy laminates. FR stands for "Flame Retardant" and means that the material meets the UL94V-0 standard for the flammability of plastic materials.
Solder mask coatings can reduce impedance by up to several ohms.
Controlled impedance is important for solving signal integrity problems, which are distortion-free propagation of signals.
The impedance of a circuit board trace depends on: trace width and thickness. The height of the dielectric layer between the signal trace and the reference plane. The dielectric constant of the dielectric material used in the circuit board.