User guide

When to Update the Minor Rev of a Part Number
PCN Process User Guide (301945-A)
Parts and Part Numbers: E-7
PCB Assemblies
A major revision is required for the following types of changes:
• Changes that are not backward compatible, that is, where rework cannot bring
old units up to the latest revision: function, form, or fit (e.g., different physical
package or dimensions).
• Artwork spins that result in renumbering the reference designators.
Note:
Old assembly should not be planned for future production or redesign—in these cases, you
need a new part number.
• If different products will phase-in any of these changes at different times:
backward-compatible functional hardware changes (electrical or mechanical);
bug fixes; or major component rev changes that need traceability.
Custom Parts (Cables, Sheet Metal, Fabs, Labels, Bezels, etc.)
A major rev is needed for functional changes (e.g., cable pinouts); fit changes
(e.g., physical package or dimensions); form changes (e.g., dissimilar metals or
plating); or form, fit, or function changes that affect the purchased part.
Custom Parts (Manuals and Software)
A major rev is needed if the part number does not report to an order number, or if
it is not forward- and backward-compatible.
Purchased Components (ICs, Connectors, Resistors, Caps, etc.)
A major rev is required for any component that needs restricted usage (a more
restrictive mechanical or electrical spec, e.g., a height restriction or low
capacitance); or is restricted to a specific vendor.
When to Update the Minor Rev of a Part Number
The minor rev can be updated by PCNs only during pre-production, pilot builds.
After release, when the ECO process takes over, a minor rev can not be updated.
You update minor revs by making the types of changes to a part described in this
section. Minor revs are always updated via
bom_upload
. (Major revs are updated
via
partmgr
.)