Medical PCBs

Many critical factors must be taken into account when designing a PCB for the medical field. Most prominent are checks and balances, split planes, component selection and cross referencing when applicable, fabrication and assembly drawings, and test coverage.

Major and minor checks and balances are especially important. That’s because any error or miscue can have devastating consequences. A good rule of thumb is Murphy’s Law will prevail at some point during a design.

Therefore, it is good practice to have another set of eyes ready to check all critical aspects of the layout. For example, the double check to assure proper component footprints or making sure a silk screen is correctly associated with a given component.

There are no shortcuts with medical fabrication. Quality is of the utmost importance. For both the OEM and CM, this means the fab shop selection calls for ISO and/or mil spec certification.

Also, it’s a good idea to maintain an incoming quality control process at the beginning stage when fabricated boards arrive at the CM’s dock. QC should include checking for multiple board aspects, such as hole tolerances, cutout verifications, board dimensions, and surface finishes, the CM should be aware of the tradeoff’s and characteristics associated with HASL, ENIG, and OSP to avoid mistakes in the assembly. QC should also include reviewing test coupons, cross sections, TDR reports and material certifications.

Correct impedance controls calculations must be carefully implemented at the time of fabrication. Otherwise, unwanted signal noise can lead to erroneous results.

Moreover, there are proper procedures and processes at the fabrication level that must be strictly followed. Proper baking cycles performed with no shortcuts. Special consideration when mixed materials are used. Example, mixing FR4 and Rogers layers because issues could arise when these materials are laminated together due to the different temperature profiles in the lamination cycles.

For more information on Medical PCB Surface finishes, please contact us at 412-828-5322 or click here to contact us online.