Designer’s Notebook

Duane BensonNewer intelligent CAD output files reduce errors.

Manufacturing is all about taking data from the designer and delivering good working circuit boards. Well, it can be just data – as in full turnkey – or data plus some parts and or PCBs, as in a partial turnkey or a kitted job.

Regardless of whether parts and boards are sent, or if the EMS procures everything, your manufacturing partner needs good data, and a lot of it. That data are the difference between the working boards you want and need and a random jumble of expensive paperweights.

As an EMS, we need a bill of materials (BoM), the job specifications (which you give us by ordering and describing any special instructions on our website), and the CAD design files. Fab and assembly drawings are always a good idea, too. A little extra time spent on the files sent reduces risk, and that’s a very good thing.

Read more: Electronics Manufacturing Files: What We Need

Duane BensonTips for avoiding EMI and simplifying debugging.

Power distribution on a PCB can come in a number of forms. The three most common methods are:

Route power and ground.

Use surface layer floods.

Use internal planes.

Read more: Power Distribution – To Route or to Plane PCBs

Duane BensonA user’s guide to clear communication of parts and intent.

A good portion of a quality build is simply the result of clear information. One of the more important pieces of information we deal with is the bill of materials, called “the BoM.”

The BoM is a list of all the components to be placed on the PCB. The file typically includes an index number, the number of times a specific component will be used on the board, the reference designator from the schematic, the component manufacturer, and the manufacturer’s part number.

If a specific component is used more than once – a common bypass capacitor, for example – it will still only take up one line in the BoM. One field in the BoM will list the number of times the component is used, and another field will list all the reference designators for that part number. In FIGURE 1, for example, line 5 in my BoM is a 0.1 microfarad, 10V capacitor.

Read more: The Ideal Bill of Materials

Nikola KonticSome traditional routing strategies can increase crosstalk.

Read more: A Few Thoughts on Avoiding DDR4 Layout Problems

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