The buyer's checklist for qualifying alternative memory ICs

Most alternative-part failures happen before the line starts

A second source usually does not fail because the silicon is wrong. It fails at the receiving dock: the marking does not match the documentation, the reel carries mixed die revisions, the temperature grade is wrong, or nobody wrote down what was tested. This checklist is the one we run with customers who qualify our memory parts, written so your IQC team can adopt it as-is.

Step 1 — Documentation before the box is opened

• Datasheet-level comparison. Confirm density, organization, speed grade, voltage, package, temperature grade against the original part — not against a summary table someone typed.
• Compliance papers. SGS / RoHS / REACH statements for the exact part number, plus any customer-specific requirements your own QMS demands.
• Lot traceability. Ask for the lot identity now, not after a failure. If a supplier cannot tell you which lot a reel came from, that is the answer.

Step 2 — Incoming inspection

• Marking and labels. Laser marking versus printed label, part number, date code, lot code. Marking that disagrees with the label is an immediate hold.
• Package and pin inspection. Ball integrity, coplanarity, solder-ball contamination, and mechanical fit in the target footprint.
• Quantity and packing. Reel or tray count, tape pitch, and whether the packing suffix matches what you ordered.

Step 3 — Electrical verification

• DC parameters. Operating currents and leakage across the supply rails you actually use.
• AC parameters and timing. Access time, setup/hold margin and refresh behaviour at the speed bin you specified.
• At temperature. If the design runs industrial temperature, test at industrial temperature — a commercial-grade part can pass at 25 °C and fail at the edge of the industrial range. We hold dedicated industrial-grade lines (−40 to +95 °C) for exactly this reason; examples include HGD32G16N18I and HGD44G16N32I.

Step 4 — Functional validation on your platform

This is the step that qualifies the part. A datasheet comparison says a part should work; only your board says it does.

• Boot and enumerate on the real controller, at the real bus speed.
• Stress and margin testing — memory test patterns, sustained load, thermal soak. Die revisions can change margin under load even when the part number does not change.
• Re-run on the second lot. One good lot proves one lot. Repeat the functional test when the lot changes; that is the only defence against die-revision drift.

Step 5 — Burn-in and screening

Burn-in removes the early-failure population before it reaches your line. Whatever your volume, define the screening that a supplier must perform and require the record to travel with the shipment. Each lot is validated with visual, electrical and functional checks on mainstream platforms, and ships with traceable records.

Step 6 — Sign-off and change control

• Freeze the approved specification. Write density, organization, speed bin, voltage, package, temperature grade and supplier part number into the approved-parts record.
• Define the change trigger. Any new lot, die revision, marking change or packing change re-opens the qualification — decide this before the first shipment, not after a line stop.
• Keep the evidence. Inspection records, test reports and sampling results should be retrievable by lot for the life of the program.

Six questions to send with your RFQ

How a supplier answers these tells you more than any brochure. We answer them the same way for every enquiry:

1. Which original part number does this replace, exactly as marked? Not "DDR3 4G" — the full marking, including letter grade.
2. What is the parameter table? Density, organization, speed grade, voltage, package, temperature grade, side by side with the original.
3. What testing is performed on the lot you will ship? And can we see a sample report before ordering?
4. Is this commercial or industrial grade, and can you hold the grade consistently across lots?
5. What is the sample quantity, cost and lead time? And is the sample cost credited against a production order?
6. What happens in year five? Buffer stock, price-lock and long-term supply commitments are the questions that matter for a long-lifecycle product, and they should be settled in the first quotation.

The documentation pack you should receive with every shipment

Ask for the pack before the first shipment, not after an incident. A supplier who cannot produce it on request is telling you what the lot will look like.

Red flags worth stopping for

• Marking that does not match the label, or labels that appear laminated over.
• No lot traceability, or "various lots" as an answer.
• Documentation for a different temperature grade than the part supplied.
• A price that is far below the market without a technical explanation for why.

How a sample plan typically runs with us

Samples start at 10 pcs so validation happens on your board before any production commitment, and the sample cost is credited against your first production order. Stock lines dispatch in 48 hours from Shenzhen with per-lot test reports; long-lifecycle programs can be price-locked. Pricing on stock lines is typically 5–10 % below major distributor list prices — we would rather quote a defensible number than a dramatic one that fails procurement review.

Send one part number and we will return the cross reference, the parameter table and the documentation set for your IQC to review: request a quote, or search it in the cross-reference tool.