When do I need to choose components?

It can come in handy to choose components early in the design process. This is the best way to ensure there are no conflicts between the actual design and the components being assembled. If you factor in component sizes from the very beginning, component space and sizes are no longer a concern and the PCB assembly process can proceed without barriers.

Can I mix technologies?

Our best advice would be not to. The payoff of a single through-hole, for example, doesn’t outweigh the additional time and money spent. It would be more efficient to either use multiple through-holes or none. If you do use through-hole technologies, placing all through-holes on one side of the board will reduce manufacturing time.

How do I pick the appropriate package size?

It is important to choose the appropriate package size while in the PCB design phase. Ideally, you would only choose smaller packages when there is a good reason to; otherwise, lean toward bigger options. In too many cases, electrical engineers choose unnecessarily small component packages. This can create issues in terms of assembly yield, as it is more difficult to touch up and rework smaller components. Depending on the amount of rework needed, it may be more cost-effective to completely rebuild the board the remove and solder on new components.

What type of components should I go for?

Component availability can potentially cause significant delays. You can avoid this issue by checking the availability of all components before beginning the design. If there are parts which require long lead-times, they can be ordered early and be consigned to the PCB assembly vendor. The assembly vendor can also handle the procurement of the more widely available parts, so every component will be ready and waiting when your boards are ready to be assembled.

Should I keep my BOM up to date?

A BOM is a key aspect of both design and assembly. If there are any issues in your BOM, the assembly house will place the project on-hold until the issues have been resolved with an engineer. One way to make sure your BOM is updated is to review your BOM any time there is a change in your design. When you add new components to your schematic while the layout is in process, make sure you’ve also updated the BOM with the correct part number, description, and component values.

How important is the footprint development?

Component footprints are another major aspect of layout design. A PCB master will make sure their footprints are created accurately as per the land pattern recommended in the datasheet. It is very important to use the numbering key correctly from the datasheet to identify the correct part and its land pattern. Reading the datasheet incorrectly will result in an incorrect footprint, which could require a complete redesign and re-fabrication of the boards.

Do I need to pay attention to part-to-part spacing?

One of the frequently asked questions posed by designers who are not yet PCB masters is in regard to the component-to-component spacing. Placing a component too close to another component can create various issues which may require redesign and refabrication, which results in a loss of time and money.