6 Common PCB mistakes

U43A0069

1. Lack of planning

With PCB layouts, preparation is the most important part of the job.  The amount of time spent preparing will affect the success of the design.  Selecting the right PCB design software is the most important; each having advantages, disadvantages and limitations.

Each PCB is unique it it’s own way.

Some areas of the design are more important than the rest, for example power supplies, impedance signals, DDR, address and data bus.  If these areas are not completed before the rest of design, precious time is lost and considerable effort is then spent reworking the layout.

Setting up rules and constraints are there to guide from the placement stage till the gerbers are completed.  When a PCB is planned correctly, the rest of the design will become a much simpler process.

 

2. Constraint rules

There isn’t anything more powerful than the human mind, unfortunately it is not perfect!

There are lots of things to think about with a PCB design, and it is easy to get lost with all of the information.  By using the tools available from PCB software, constraints can be implemented; spacing, keepouts, length matching, propagation delays.

Once these rules have been implemented, the designer can focus on other areas of the layout.

 

3. Poor Communication

As PCBs become more complex, the communication between engineer and PCB designer is essential.  By eliminating any placement or routing issues early on can save on costly reworks.

It is very important for the engineer to review the circuit board as often as possible.  Using on-line meeting tools can allow the engineer to inspect the board in real time and discuss potential issues.

By setting out clear objectives and agreeing on them from the start of the layout can give the designer a better understanding of what you want to achieve and can shorten time-to-market.

 

4. Using ineffective layout techniques

PCB layouts are becoming more complex thanks to advancements in electronic technology.  Problems such as electrical noise, crosstalk, impedance mismatch, timing issues, ESD – all need careful consideration.
Practical PCB design rules, board stackup, PWR & GND planes, decoupling capacitors, faraday shields – these are valuable when used correctly.
Reference designs provides the optimum solution to meet requirements for complex layouts.  Some of their suggestion may be difficult to achieve, but they do give some insight on how the PCB should be designed correctly.

 

5. Forgetting to backup data

Backup completed designs, no brainer.  Hundreds of hours are invested in most designs, eventually all designs will have to be modified.

Obsolete components and new technology will demand the board is updated.

If the original files have been lost, the whole project will have to start again or be scrapped.  The use of a cloud is a cheap and easy solution to backing up data.

 

6. Becoming a One man island

Any experienced PCB designer may look on a completed design and see perfection.  It is easy to get “tunnel vision”; concentrating on one area of the board and missing a detail on another.  A colleague not as involved in the project can be more impartial and provide an objective and invaluable insight.

Regular design reviews can help detect future errors and allow individuals to share experiences and knowledge.

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