Direct answer
An MPN is the manufacturer’s exact part identifier. A SKU is usually an identifier created by a distributor, company, warehouse, or ERP system. For electronic component monitoring, the safest sequence is to identify the exact MPN, collect supplier observations against that MPN, and only then map the result to an internal SKU or BOM line. Treating every identifier as the same can turn a packaging change or a different seller listing into a false inventory event.
Who this is for and what it does not promise
This guide is for teams importing BOMs, building purchasing workflows, or watching parts across multiple suppliers. It is useful when one internal item can be sourced from several channels. It does not define a universal SKU standard, and it does not claim that two similar-looking part numbers are electrically interchangeable. Substitution still requires engineering approval.
The four identifiers to keep apart
| Identifier | Usually owned by | What it is useful for |
|---|---|---|
| Manufacturer part number (MPN) | Component manufacturer | Exact product identity and technical/lifecycle lookup |
| Distributor part number | Supplier or distributor | Finding the supplier’s listing and checkout record |
| Internal SKU | Your company or ERP | Purchasing, warehouse, accounting, and planning workflows |
| BOM reference | Design or manufacturing team | Where and how the component is used in a product |
The DigiKey ProductSearch API explicitly supports searches using a manufacturer part number or a DigiKey part number. That distinction is a practical reminder: a supplier’s own number can help find a listing, but it is not automatically the manufacturer’s identity.
Why early normalization causes false alerts
Packaging is part of the purchasing context
Two listings can point to the same underlying family while differing in packaging, quantity, or customer-specific availability. If a monitor discards those fields, a price or stock change may be attributed to the wrong item.
Internal SKUs can represent business decisions
An internal SKU may bundle a preferred supplier, approved substitute, packaging choice, or regional purchasing rule. That is valuable business context, but it should not replace the external identity used to query the supplier.
Search matches are not confirmations
A broad search can return near matches, alternate packages, or similarly named parts. A monitoring system should keep “candidate found” separate from “exact MPN confirmed” and from “current offer observed.”
Lifecycle status needs the exact product
Active, NRND, EOL, and obsolete signals apply to a particular product identity and source. If multiple variants are merged, a lifecycle notice for one item can incorrectly affect an entire internal family.
A safer MPN-to-SKU workflow
- Import the raw BOM reference and preserve the original text.
- Normalize manufacturer and MPN without deleting meaningful suffixes.
- Resolve supplier listings and store distributor numbers as source-specific fields.
- Record package, quantity, region, currency, and lifecycle context.
- Map the verified external identity to an internal SKU with an explicit relationship.
- Monitor each source-specific offer, then roll up changes to the SKU only with a stated business rule.
- Require engineering review before treating an alternate MPN as an approved substitute.
Product workflow
Chip Monitor starts with exact part-number monitoring rather than a generic category search. Its quick lookup and supplier integrations are intended to help teams follow stock, price, and lead-time changes while keeping the source and last-checked context visible. For plan limits and notification options, see the monitoring plans.
The same monitoring plans page shows the public watchlist and notification options.
Evidence boundary
Part-number conventions differ by manufacturer and supplier, and a similar suffix does not prove interchangeability. Always confirm the manufacturer datasheet, package, electrical requirements, approved vendor list, and final supplier record before purchasing or changing a BOM. This article describes an identity and monitoring method; it is not an engineering substitution approval.