Over engineering a PCB - Page 1
Forum section: electronics / projects

author: Northy
author_rank: Regular Contributor
timestamp: August 25, 2020, 04:27:53 pm
content: Hi all,While listening to one of the Amp Hour podcasts Dave just happened to quickly mention over engineering a PCB. He mentioned star grounding, via stitching etc as examples.I'm interested in discussing this and when do people think these techniques should and shouldn't be used, along with other aspects of PCB design.Thanks,G

author: b_force
author_rank: Super Contributor
timestamp: August 25, 2020, 09:28:09 pm
content: This just highly depends on the type of board and circuit.When there is only a relatively slow digital circuit with no much big current going anywhere except for a few microcontrollers or so, you can basically do whatever.It's going to be a very different story when there are (sensitive) analog signals involved.I personally think that people really overdo stitching, especially when there are already solid connections to ground going.It can be beneficial when having multiple ground layers connected together, although it's a bit debatable if that has any benefits.Also heavily depending again on the type of circuitry and frequencies involved.Personally I don't think over-engineering a PCB is ever a bad thing in the essence.I read that as; trying to make the best possible design possible.The more you practice that approach, the more it becomes your standard way of thinking, the easier (and faster) it gets.In the end there is absolutely nothing worse than having to troubleshoot and poorly designed PCB.In fact, it can be sometimes really difficult to find out it actually was a PCB design problem.So better safe than sorry, and having to call back hundreds of boards (I think we all have been there, once in our life)That being said, I have seen people going all weird about slow to medium speed signals like I2C and I2S tracks.

author: Northy
author_rank: Regular Contributor
timestamp: September 16, 2020, 09:49:08 am
content: Thanks for the reply.I think I'm of the same opinion, why would you not make something as good as it can be?G

author: b_force
author_rank: Super Contributor
timestamp: September 17, 2020, 01:58:47 pm
content: Quote from: Northy on September 16, 2020, 09:49:08 amWell obviously often it's also a time constrain thing.But it's like most things, the more you do it, the better and faster you get at it.I am often surprised how low certain standards are at certain companies.As a result they wonder why products fail and have issues, go figure....

author: sokoloff
author_rank: Super Contributor
timestamp: September 17, 2020, 02:53:07 pm
content: Quote from: Northy on September 16, 2020, 09:49:08 amEngineering is a matter of tradeoffs.Someone could engineer the strongest racecar chassis the world has ever seen, but that car won't win any races.Someone could engineer the longest-lasting roadway the world has ever seen, but the government won't be able to afford to pave all their roads that way.In PCB design, I think there's a point where spending additional labor on the design isn't justified. (As one concrete example, I made some PCBs for our Halloween costumes in 2018. Was my first JLC-PCB order and I knocked it out in a couple hours after dinner and fired the order off. Could I have made the board "more perfect"? Sure. It wouldn't even have cost me any more money at the fab, but the costumes would have looked and worked exactly the same in the end; all that would be different is that I'd have spent more time on it for no discernable improvement in the finished product.)

author: Northy
author_rank: Regular Contributor
timestamp: September 17, 2020, 06:44:10 pm
content: Now I can agree if you're designing a board for your own use, I was more thinking about a board that has to go into a commercial product and pass regulatory compliance testing mainly.Thanks,G

author: schmitt trigger
author_rank: Super Contributor
timestamp: September 17, 2020, 07:04:40 pm
content: Commercial products, specially high volume ones, come with severe cost constraints, and most times inflexible timelines.In those instances, one designs the product to meet the customer requirements and regulatory standards, and not a penny more.