Although none of us want to be in a position of needing emergency medical services, it is a comfort to know that EMTs are well-trained and incredibly proficient professionals. The speed with which they can assess a situation and render life-saving aid is essential. Along with the skills of EMT crews is some of the best medical equipment available today. These people and their equipment often make the difference when disaster is a heartbeat away.
The equipment used by EMTs is state-of-the-art and constantly enhanced to enlarge its capabilities. But defibrillators and other emergency tools aren’t the only devices used in the medical field. Everything from diagnostic equipment to blood analysis systems relies on electronics that must function perfectly every time. This level of reliability requires absolute precision and quality in the design and manufacturing of PCBs for medical devices, which we will examine in greater detail here.
Design Expectations of a PCB for Medical Devices
To design a circuit board for use in medical equipment requires following PCB design best practices to produce the highest quality. These practices include:
- Selecting the highest quality parts.
- Attention to detail during circuit development to create a schematic that is logical to follow.
- Using circuit simulation and PCB analysis tools to ensure function and cut back on PCB prototyping.
- Careful component placement and trace routing during PCB layout to create a board that can be manufactured without errors.
Medical equipment also has to operate flawlessly, whether used in the field, operating room, or analyzing test results in a lab. Doctors, nurses, and technicians don’t have time to deal with equipment that works intermittently or not at all. Additionally, the equipment must be robust enough to work in various environments, including chemicals, fluctuating temperatures, and fluids. Another aspect of the equipment is that it must be safe to operate in these different environments without worrying that it could potentially shock the user or the patient.
One aspect of designing medical equipment to operate in different environments is to ensure that it won’t be affected by electromagnetic interference. Since medical equipment’s environments can change drastically, PCBs must be designed to thwart EMI in any situation. Engineers should reference many EMI standards during medical equipment design, starting with IEC 60601-1-2. Some of the practices that PCB designers need to incorporate to avoid EMI when designing medical equipment electronics are as follows:
- Full ground planes to provide shielding and unbroken signal return path for sensitive nets.
- Isolation of analog and digital circuitry in mixed-signal circuit boards.
- Minimize trace lengths, and use wide traces for power supply circuitry.
- Use bypass capacitors on every power pin for active components.
To design a circuit board that will meet all of the milestones required of medical equipment requires some specific engineering capabilities, which we will look at next.
Engineering Requirements for Medical Circuit Board Design
A circuit board designed for medical equipment requires a high level of engineering to ensure the final product performs as expected. These four areas of the design exemplify the kind of engineering expertise medical devices require:
- Design review: The PCB layout needs to be checked for its manufacturability to ensure there aren’t any problems during fabrication and assembly. The design should also have its circuitry validated, and its components checked for form, fit, and functionality.
- Part sourcing: The design also should have its parts reviewed for price and availability, and any new parts should be sourced from a reputable network of suppliers.
- Quality: The board should also be reviewed for testability to verify its assembly or to conduct a full functional test. The design should also be checked for compatibility with the overall system requirements.
- Documentation: Another important aspect of medical electronics is the requirement of ISO 13485 for full traceability of the parts and materials used for their manufacturing. The design must be carefully documented to provide the required history tracking.
Although design groups can do a lot to prepare their designs for manufacturing, it typically takes the resources of a PCB contract manufacturer to provide the level of engineering that is needed. For instance, PCB CMs have a component engineering group that can recommend alternate part choices to improve performance, lower prices, or increase availability. The PCB CM can do a lot of engineering on a medical circuit board to refine it and prepare it for the highest quality and best yields in manufacturing. Next, we’ll look at some of the other attributes and qualifications you should expect from your medical circuit board manufacturer.
What You Should Expect from the PCB CM Building Your Medical Equipment
Here are some of the capabilities you should expect from a circuit board manufacturer to build your medical equipment circuit boards:
Certifications:
There are different standards for different industries, but at a minimum, a PCB CM should be certified in ISO 9000 or 9001. This standard covers the quality and reliability requirements of electronics design, manufacturing, and testing. PCB CMs should also be fluent in standards like IPC-A-610, which covers the acceptability of electronic assemblies, and CFR 820, which establishes a system for validating manufacturing and quality control.
Traceability:
We touched on traceability above, but its importance can not be overstated. The FDA enforces product identification in medical equipment, and manufacturers of medical electronics have to have a system to trace every detail of what they build. These details include parts, materials, and other aspects of manufacturing, such as test results, certificates of compliance, product configurations, and other product data. This data is necessary for product or part recalls and future enhancements made to the device. ISO 13485 specifies the criteria for tracking systems, and the PCB CM should be certified in this standard and have a tracking system in place that conforms to its requirements.
Reduction of hazardous materials (RoHS):
Electronics sold in the European Union are now required to be built lead-free. The PCB CM building your medical equipment should have a lead-free manufacturing process that is completely isolated from their regular soldering processes.
Quality:
The PCB CM you use to build your medical electronics must have a reputation for quality and the production capabilities to produce high-quality circuit boards. They need to be able to provide the front-end engineering to ensure your design is ready for manufacturing and the facilities and skilled personnel to build the product. At VSE, we have the services, personnel, and manufacturing equipment to build your electronics. We carry certifications in ISO 9001, ISO 13485, and are an IPC corporate member with certified IPC-A-610 trainers on staff. Give us a call to find out how we can help you with your next medical equipment project.
