How to Design a PCB for Medical Applications
Printed Circuit Boards (PCB) used in medical devices and applications are meant to provide aspects of quality, reliability, and repeatability. They also need to comply with the ISO 13485 standard, which elaborates on how the PCB needs to meet requirements of strength, durability, and traceability, apart from the previously mentioned aspects. All of these requirements can be met with the design of the PCB. However, a PCB for medical applications has some unique design requirements that need to be adhered to.
Draw the initial schematic.Take the necessary information from the client, and finalize the details of the PCB, such as PCB type, materials, power, etc. Then create a schematic drawing with all the necessary specifications written on one side.
Scan and prepare the layout.Scan the drawing and upload it onto the PCB design software. Using the previously written specifications, begin adding the various requirements that were finalized by the client.
Pay attention to critical factors.PCBs for medical applications require certain factors to be given importance. Take into account aspects such as split planes, pin numbers component selection, and sequencing. Ensure that the silk screen is provided with the correct component in the design.
Ensure proper splitting of power.The diversification of ground planes and electric power is essential for reducing the level of crosstalk and noise in the PCB. Design the ground planes in a manner such that there will be few high Signal-to-Noise ratios (SNRs).
Provide multiple ground layers.In the PCB layout, create multiple ground layers at the base of the PCB. Not only do the ground layers help in reducing the noise and SNR levels, but they also help in the quality of the PCB’s performance and its overall reliability.
Review the bill of materials.This task has to be performed by both the PCB designers and the OEM designers. Review the Bill of Materials (BOM) together. Check to make sure that the chosen components consist of the exact levels of tolerance required for the PCB.
Check the components.Check all the components that have been chosen. Review their data sheets so you know you are using only the best components.
Make an alternate component list.If the chosen component does not match up to the requirements, keep an alternative ready so that you don’t lose any time in the PCB design process.
Check the alternate components.Just as you did with the original components, check the alternate components as well. Take a look at their performance history as well as the data sheets. This needs to be done to determine their success and failure ratings. Treat the alternate components with the same care and attention that you gave to the original components so that you will be prepared, should you have to use them.
Create an assembly drawing.As the design and layout phase is coming to a close, the designer has to also create an assembly drawing. This drawing is used to avoid any guesses or mistakes during the fabrication and assembly processes. Also, jot down detailed notes about all the revision levels or REV if there are any changes in the original design.
Indicate the test points in your design.Identify the various points in your design that can be assigned on the board for testing purposes. The more number of test points provided, the better the chances are of reducing errors during the testing phase.