Choose parts

A part counts as chosen when it has all four of these:

• an exact orderable part number;
• a datasheet that proves its ratings;
• stock where the board will be built;
• a footprint checked against that exact package.

Stock, prices and lifecycle change monthly. Look them up, never answer from memory, and give the date you checked.

1. Requirements

Take the worst cases from kicad-schematic-review and choose ratings with margin. Easy to miss:

• Ceramic capacitors lose capacitance under DC bias. Where the value matters (regulator input and output, timing, filters), read the maker's bias curve at the working voltage; high-value parts in small cases lose most of theirs. Rating at twice the working voltage is enough only for small decoupling caps.
• ICs: every absolute maximum the circuit can reach, not only the supply.
• Ordering variants: a value field may hold only part of the number ("TLV9061"). Read the ordering table, list the variants that fit (package, temperature, options), and let the user pick when it isn't obvious.