Medical Device PCB component change


Involved In Discussions
We have a medical device where we now are changing 2 components in the PCB. Does this change count as a substantial change or not? Our main standard is -2-57 (which in turn points to 60601-1 ed 3 wo amn 1).


Super Moderator
More information will be needed. What are the components? Have you done any risk analysis to determine the potential impact of the change (impact to existing risk controls, any new risks posed, etc.)? Does the change alter the functionality?

Mark Meer

Trusted Information Resource
As yodon says, your risk analysis is critical.

Consider such things as:

1. Does changing the components potentially invalidate previous testing (e.g. EMC)? If so, re-testing is likely required. If not, document your analysis, and justify why the change doesn't impact previous test-results.

2. Does the change affect function, or device specifications? If so, this is likely a significant change.

3. Does the change affect your previous risk-assessments? Are these critical components necessary for safety/risk-mitigation?

The FDA has a pretty comprehensive document on assessing the significance of a change.
Last edited:


Involved In Discussions
One of the components is a "common-mode choke". It's placed in the DC (48v) feeding path of the lamp (MD) and have the purpose of acting as a filter for common mode noise that might have been induced by electromagnetic fields on the dc feeding cable between the power supply and the lamp head. It also filters noise. The parameters that are important for its functionality such as physical shape, its ability to make resistance to common mode noise and its ability to withstand the votage and the current used by the lamp are not changed. Operating voltage is changed from 250 v to 300 v, which is well within the specifications.

The other comp is a P-channel MOSFET. It controls the power on/off of the lamp. Its specification parameters are well beyond what is required for achieving the functionality of the MD.

No new tests are necessary, previous testing is still valid, function and specification of the lamp remains the same before and after the change. And right now we have a justification as to why re-testing is not necessary.
So what do you think? Significant or not?


I would suggest that, from a safety perspective, your changes are probably not significant and would not change test outcomes.

However, both components are significant from an EMC perspective.
How the FET switches could affect Radiated Emissions.

The CM choke is clearly directly impacting the EMC outcome - careful examination of your EMC test report and your design history file should enable you to understand why/when it was included so as to identify the critical tests to show continued compliance.
Top Bottom