The Superconductive Circuit Board

    Can FR-4 Printed Circuit Boards operate in very low temperatures?

    Mon, Feb 03, 2020 @ 06:45 AM Omni Team Printed Circuit Board Design, Printed Circuit Board Commentary

     

    The quick short answer is "Yes...,"

    One clarification is needed before addressing this question, though. 

    FR-4 Laminate PCB Material-1Originally "FR-#" was only meant as a NEMA designation for base epoxy material that was "Flame Retardant". Unfortunately, it has become industry standard to call the most common used laminate (woven fibreglass-reinforced epoxy) merely by the name of "FR-4", and in this sense, the designation lost its significance and is now widely understood as a laminate name.

    With that clarification out of the way, we can share with you that our customers have been successfully using "FR-4" (woven fibreglass-reinforced epoxy) at cryogenic temperatures for years and counting.

     

    Our customers have also been using other base epoxy material called "G-10 CR" (woven fibreglass-reinforced epoxy) and other "Specialized" laminates, which are also Flame Retardant. These specialized laminates are mostly built-up with polyimide or ceramic (woven fibreglass-reinforced polyimide/ceramic) and, therefore, not referred to as "FR-#."

    These customers have paired their PCB laminates with equally compatible components; they have also applied DFM (Design For Manufacturing) techniques on their layouts and operation logistics.

    All of these things together have resulted in reliable PCBAs (Printed Circuit Board Assemblies) operating at very low temperatures in the field.

     

    Their feedback is this:

     
    "One of the main issues is not how long something stays cold but rather how many thermal cycles it has to endure."

    "Thermal cycles put mechanical stress on your electronic circuits, for example, Thermal Contraction and Expansion, and physical transformation of your materials, for example, Tin Pest, which is detrimental to solder joints."

     

    For you to select the correct laminate for your PCB, you need to consider the electrical, mechanical, chemical and thermal properties of each laminate and match them with your intended application, and you do this following DfX methodologies.

     

    Remember that the properties of these laminates or base materials will give your PCB the electrical isolation and mechanical strength it requires in the field.

     

    Some laminate providers are:

     

    Omni Team

    Written by Omni Team