Page Comparison

Footprints

• Component Centers

  • Where they belong

  • Is it the same for everyone, or stored locally by user?

  • Define a width and length for crosshairs

• Courtyards

  • Can silkscreen be outside the courtyard?

  • Set specific courtyard distance from component outline

  • Set specific widths for courtyard + component outline

• Silkscreen/Top Overlay

  • General guidelines for silkscreen markings

  • Pin 1 dot - define radius, thickness, min distance from pads

• Assembly

  • Would be good to articulate exactly what things are permitted here (some components have boxes/other markings in addition to the 3D model

• Pads

  • Establish annular ring convention?

  • Should we include tolerance data?

• Component Outline

  • Make sure it’s clear that the outline doesn’t include the legs of the component

  • Currently (to my knowledge) there’s no requirement or procedure to verify the validity of a 3D model of a component downloaded from online. It seems odd to base our component outline off of this without first verifying the 3D model dimensions, since this can in turn affect courtyard and component spacing

• How should we handle components which say they’re (for instance) 8-SOIC, but recommend a footprint that’s different from and not encompassed by the existing 8-SOIC footprint?

• Proper procedure if you can’t find a good 3D model online

• Guide on how to import footprints from Ultra Librarian/snapEDA/etc.

• Should define a consistent orientation for footprints (i.e. connectors should face upwards, SOIC packages should have pin 1 at the top left)

Symbols

• define standard convention for Mechanical pin designators (M? vs. MNT? or similar)

• Remove Mounting and fiducials and such from BOM

Component Parameters

• Case/Package vs. Package parameters?

• Using typical vs min/max columns. Using recommended maximum vs absolute maximum

• Would be good to add a description to Voltage Rating on connectors to specificy AC or DC

• It seems like the auto-generated description is nearly always wrong on components, even when part choices is correct. We might want to standardize using the “Detailed Description” from Digikey instead

• Do we have a standard for what to do if it lists multiple packages?

• We generally need to figure out an approach to how to handle the Package/Case parameter of ICs. Right now we’re using the Package/Case parameter on Digikey, which seems to list standard packages which may be compatible with the supplier device package. But it’s unclear where they derive this from, and whether its trustworthy. Suppliers will also often have their own Supplier Device Package which may differ from standard footprints listed under Package/Case. Example: MAX16998AAUA+

  • Potential solution: we could just say make the Package/Case field match the footprint we use. And that when picking a footprint, you should exhaust all standard packages listed in Package / Case before using a supplier device package footprint.

Component Revision

• Component States

  • Proper procedure if you review a component then catch an issue

  • If “In production” part has a minor issue, do you bother tweaking it? And if so, do you return it to “in production” or just make it “Reviewed”?

    • If this happens, and a new “reviewed” revision is created, do you have to roll back all prior approved revisions to drafts?

Schematic Guidelines

• Should we eliminate the units (ohms, Farads) from passives, since its assumed? (i.e. 100n instead of 100nF)

• Should we go to a standard of using net labels like “3V3” instead of “3.3V” for improved readability?

  • Similarly, we could do “4k7” instead of “4.7kOhms”

• Should we define standards for use of hierarchical vs. more flat schematic organization?

  • Do we require one or recommend one

• Setting a max of 3 wires per node to improve readability

Layout Guidelines

• Need to emphasize somewhere that component layer pairs should get added to the PCB file as well

• Need to emphasize that standard design rules must be added

• Explanation for layer stack manager and impedance profiles

  • Potentially add JLC standard impedance matched stackup to default project template?

...

• Generally needs an update

• Need to make a default stack up and save that file + make a page on stack ups + add to project template

Design Reviews

• Need to have all DRC errors resolved before PCB review

• We need a guide for how to place orders (what settings we like, how many, etc)