BOM Approved Alternates

The bom.alternates configuration key lets teams document approved substitute parts for a primary MPN so that supply-chain risk checks can distinguish an actively managed single-source decision from an oversight.

Why Use Alternates?

The bom.single-source rule flags BOM rows where only one supplier is listed — a signal that availability risk has not been addressed. When a team has already validated a drop-in replacement but chooses to order only from the primary supplier, the bom.alternates list documents that decision and silences the finding.

Configuration Format

Add a bom.alternates list to boardreadyops.yml. Each entry identifies a primary MPN and one or more approved alternates.

bom:
  alternates:
    - mpn: "RC0603FR-0710KL"
      alts:
        - mpn: "RMCF0603FT10K0"
          manufacturer: "Stackpole Electronics"
          note: "Verified drop-in replacement — same footprint and rating"
    - mpn: "LMR33640ADDA"
      alts:
        - mpn: "MP2359DJ"
          manufacturer: "Monolithic Power"
          note: "Tested at Rev1 prototype; requires layout review at >500mA"
        - mpn: "TPS62172DSGR"
          manufacturer: "Texas Instruments"
          note: "Pin-compatible if C_out ≥ 10µF"

Fields

Field	Required	Description
mpn (top-level)	Yes	Primary MPN in the BOM that this entry covers
alts[].mpn	Yes	Approved substitute MPN
alts[].manufacturer	No	Manufacturer of the substitute (informational)
alts[].note	No	Free-form note, e.g. test result, footprint caveat

MPN matching is case-insensitive and trims leading/trailing whitespace.

Behaviour

When bom.single-source encounters a BOM row whose MPN matches a bom.alternates entry (regardless of how many supplier columns are populated), the finding is suppressed. The alternates list is visible in the config file and therefore auditable via version control.

Example — Prototype vs. Production Workflow

During prototype, a team may source only from one supplier. Adding the validated alternate to bom.alternates documents the decision for future reviewers without blocking the prototype build.

For production, sourcing teams can use the alternates list to onboard a second supplier, at which point the BOM will show two supplier columns and bom.single-source will no longer fire — regardless of whether the MPN is in the alternates list.

Alternates and the Evidence Bundle

Alternates metadata is visible in the boardreadyops YAML config, which is included in the release evidence bundle. Reports and PR comments will reference the bom.alternates config key in any finding that was suppressed because of it.