The Superconductive Circuit Board

    Mike Lesiak


    Recent Posts

    Understanding PCB Manufacturing: Impedance Control

    Printed circuit boards with impedance requirements demand a high level of precision.

    Image courtesy of Zmetrix

    For standard circuit boards, a PCB manufacturer is given a set of patterns - copper patterns, hole patterns, ink patterns, which are combined into a single circuit board with all the pattern sizes and positions within certain tolerances. Failure to meet a certain size or position with the specified tolerance can be cause for the circuit board to be rejected. If a trace has been defined as an impedance control trace, it is not the trace size which is strictly defined, but rather the impedance. While a nominal trace size will be provided in the Gerber layer, it is understood the circuit board manufacturer can vary trace width, height, and dielectric thickness as long as the final impedance is within tolerance.

    Understanding PCB Manufacturing: Electrical Testing

    PCB manufacturing facilities routinely perform Electrical Testing with “Flying Probe” testers which are well suited to smaller production runs.

    For short runs, the flexibility of quick set-up ensures cost effective Flying Probe tests outperform the lead-time, cost and fixed designs of dedicated test beds. With Flying Probe tests, no fixtures need to be prepared, only data files.

    Flying Probe tests are able to reveal not only shorts and opens produced by the manufacturing process but have also been known to expose design errors.

    Understanding PCB Manufacturing: Multilayer Assembly

    One of the more interesting activities routinely associated with PCB manufacturing is the process of assembling multilayer circuit boards.

    At any given time 40% of our PCB manufacturing at Omni is producing multilayer circuit boards, so understanding the process is important. Layers of copper foil, prepreg and core material are sandwiched together under high temperature and pressure to produce multilayer assemblies. Pressure is needed to squeeze out air while heat is required to melt and cure the thermosetting “prepreg” adhesive which holds the multilayer PCB together.

    Printed Circuit Board Design Techniques and Best Practices

    Using a few simple techniques can help ensure a more robust printed circuit board design which can also help you save money.