PCB Design Hints

1. Fiducials - For SMT layouts place a Fiducial in all four corners of the PCB about .125" to .250" in from each edge. Our standard fiducial is a solid 40 mil circle on the copper layer with a 60 to 80 mil solder mask opening. If the assembly has SMT components on both sides, place the Fiducials on both sides. For fine pitch parts (15 mil or less) use component Fiducials.
DO NOT Place a Drilled Hole in the Fiducial.

2. Panels - Allow us to panelize the PCB. We can place the PCBs in a panel that will increase production efficiency, reduce PCB material cost, and assembly time.

3. Polarized Components - Have all polarized components (Diodes, Capacitors, ICs, etc.) going the same direction if possible. If components must be going different directions, use a silk screen outline that can be seen when the component is in place. Use outlines where polarity is easily seen. Avoid using small dots, squares and the number one. Never mix polarity symbols on the same assembly.

4. Double Sided Boards - For mixed technology PCBs try to place both SMT and Through Hole components on the same side. For PCBs where you intend for the SMT parts to be wave soldered with the Through hole parts, placing multi-leg SMT components on the solder side requires advanced layout skills and non-standard SMT footprints to assure the best quality. For two sided SMT assemblies, try to place all the ICs and fine pitch parts on the same side.

5. SMT Footprints - Always use IPC-SM-782 footprints. NEVER assume that the footprints that came with your CAD layout software are IPC standard. Some special components may say that they are in standard packages but are not. Always check the recommended footprint from the component manufacturer. For instants, some surge protectors look to be in standard 0805 packages, but checking the manufacture's recommended footprint shows that they are not. Never use a via as a mounting pad for components in BGA packages. The geometry of the solder paste openings is critical to the successful production of most components where the lead pitch is less then 25 mils, each kind of package has it's own set of rules.

Reducing Tooling and Assembly Costs

1. Most Costly - Designs that are one up, not panelized, with Gerber output only. Gerber files are text files that are used to duplicate each conductive copper plane on a PCB using a photoplotter. The Gerber files only create a picture of the copper plane and contain no design information. We can extract design information, but it is the most time consuming and least accurate.

2. Less Costly - Designs that are panelized (remember we need to do the panelization) with Gerber output including solder paste layers, Bill of Materials (BOM), and Pick and Place files. The BOM can be either in Excel or Text format. The Pick and Place file should be in text format.

3. Least Costly - Designs that are panelized and laid out using one of the CAD layout packages listed below. Design output per the instruction (click on the software name for complete output instructions). Gerber output including solder paste layers, and Bill of Materials (BOM). This is the least time consuming and most accurate.

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Last Modified 11-16-27