Short answer: Protect a product from component shortages at design time, not at order time: approve at least two manufacturers for every commodity part (resistors, capacitors, discretes, connectors), check the lifecycle status of every active component before layout, design footprints and pinouts that accept alternates, keep a buffer of 3–6 months for single-source parts, and let your EMS partner watch end-of-life notices and propose replacements. Comtec Labs applies these rules in every DFM review and proposes alternates in every quote.
Where shortages come from
Three sources: market allocation (demand exceeds capacity, typically MCUs, MOSFETs, power management ICs), end-of-life (EOL) notices as manufacturers retire families, and single-source parts with unique footprints. The first is cyclic, the second is permanent, the third is self-inflicted and the easiest to prevent.
The six rules
| # | Rule | How |
|---|---|---|
| 1 | Two approved sources per commodity part | AML (approved manufacturer list) column in the BOM; the EMS buys whichever is available |
| 2 | Lifecycle check at design time | Active, NRND (not recommended for new design) or EOL status checked for every active part before layout |
| 3 | Footprints that accept alternates | E.g. SOT-23 vs SOT-323 dual footprints, pin-compatible MCU families, 0402/0603 dual pads on space-critical boards |
| 4 | Buffer stock for single-source parts | 3–6 months of consumption held by the EMS or the customer on a call-off agreement |
| 5 | EOL monitoring by the EMS | Product change notices tracked per BOM; alternate or last-time-buy proposed before the part disappears |
| 6 | AML review every 6 months | New alternates qualified while the line runs, not during a crisis |
What an EMS partner does for you
- Sourcing from franchised distributors only, so counterfeit parts are excluded.
- Alternates proposed in the quote, marked for your approval; nothing substituted silently.
- Product change and EOL notices tracked per BOM line.
- Buffer and consignment stock on a call-off agreement.
- Last-time-buy calculations against your forecast.
Key facts
- Most allocation pain sits in fewer than 5 % of the BOM lines: MCUs, MOSFETs, PMICs, precision references.
- A dual footprint costs nothing in production and saves a re-spin in a shortage.
- Comtec Labs sources only through franchised distribution; no grey-market parts.
- EOL notices typically give 6–12 months for a last-time buy; a tracked BOM turns that into a plan.
When a part disappears anyway
The sequence is: confirm with the manufacturer, quantify remaining stock in the channel, evaluate form-fit-function alternates, run a controlled engineering change with a tested first article, and update the BOM revision. Comtec Labs runs this as a standard engineering change order (ECO) with your approval at each step.
Frequently asked questions
What does NRND mean on a component?
Not recommended for new design: the manufacturer will keep supplying it for existing products for a while but is steering new designs to a successor. Do not design it in without an approved alternate.
Should I buy components myself to avoid shortages?
Usually not. A franchised distributor account through your EMS gives access to allocation and avoids counterfeit risk. Buying yourself is sensible only for a critical single-source part you already qualified.
How much buffer stock is reasonable?
Three to six months of consumption for single-source active parts; none for commodity passives with two or more sources.
Does Comtec Labs replace parts without asking?
No. Every alternate is proposed in writing and built only after your approval.
Ready to reduce PCB surprises?
Comtec Labs offers a full suite of services to streamline your workflow:
PCB design service
PCB prototyping service
PCB component sourcing
PCB component assembly
PCB testing service
PCB repair and modifications
Printed circuit board production
PCB mass production