Impedance Control is the measure of the opposition that an electrical circuit presents to the flow of alternating current (AC). It is a combination of resistance, inductance, and capacitance and it is represented as a complex value with both magnitude and phase.
Impedance is a crucial parameter in high-frequency and digital signal transmission as it affects the integrity of the signals and can lead to signal degradation, reflection, and distortion if not properly controlled.
At PICA we evaluate and calculate the proper impedance of the board by using agilent an impedance simulation software in the pre-production stage to predict the final product impedance and ensure that it meets the design requirements of the board.
Additionally, TDR equipment is used to measure impedance through test coupons and the board itself.
We control the impedance of the board by monitoring the thickness of raw material and related process operations such as lamination, copper plating, etching and solder mask.
Factors that are considered when controlling the impedance of the board are: trace geometry, dielectric material, layer stack up, copper thickness and trace length.
The PICA manufacturing team also works with our customers to advise them on the proper design parameters are called out in the date package that result in the PCBs having the proper impedance level at completion.
Additionally, for the sake of traceability, PICA offers the option of storing the impedance coupons in house at the customers’ request.