Cross-reference and alternative parts: what has to match first
Pin-compatible is not the same as equivalent. Most substitutions that fail in production matched on the package and missed on something else.
The five things to compare, in order
1. Package and pinout. Same footprint is the entry ticket, not the answer. Check pin 1 orientation, thermal pad, and whether the exposed pad is connected to ground.
2. Absolute maximum ratings. Voltage, current, power dissipation and junction temperature. A part that is “the same” at 25 °C can be derated differently at 85 °C.
3. Dynamic behaviour. Switching frequency, propagation delay, slew rate, input bias current. These are where pin-compatible op-amps and gate drivers quietly differ.
4. Temperature range and certification. Commercial versus industrial versus AEC-Q100 is not a label; it changes the part inside.
5. Second-order specs. Leakage, offset drift, ESR, saturation current, moisture sensitivity level. This is the list that decides whether the substitute survives volume.
Three examples of “same pinout, different part”
LM358 and MCP6002. Both are dual op-amps in an 8-pin package and the pinout matches. But the input bias current differs by orders of magnitude, and the bandwidth and supply range are different. In a high-impedance sensor front end, swapping one for the other changes the error budget completely.
1N5819 and SS14. Both are 1 A, 40 V Schottky diodes. One is through-hole DO-41, the other is SMA. Electrically close; mechanically not interchangeable without a board change.
AMS1117 and LM1117. Pin-compatible linear regulators in common packages, but dropout voltage and stability requirements differ. The output capacitor is not a detail — some variants need a specific ESR range.
What to send us for a cross-reference
Send the original part number, the quantity, and any constraints you already know: package, temperature range, certification, and which specs are critical. If you have the schematic or the BOM line with values, even better. We will come back with candidates and a note on what differs — not just a list of “equivalents”.
When not to substitute
Do not substitute in safety circuits, medical devices, or anything that has passed certification without re-testing. Do not substitute a part you cannot verify the date code on. And do not accept a substitute on the basis of a datasheet comparison alone when the part is in a feedback loop — put it on a prototype first.
Frequently asked questions
Yes. Send the part number and the specs that matter; we will propose alternatives and state what differs.
Only after checking ratings, dynamic behaviour and temperature range. Pin compatibility is the first check, not the last.
No. Cross-referencing is part of quoting. You pay only if you order.
Usually yes. Sample quantities and lead time are confirmed per part.
More sourcing guides
Excel, CSV or a photo of the BOM · first response normally within 2 working hours; formal quote within 24 hours