What This Connector Is
The Amphenol FCI 87185-421HLF is a 21-position, single-row, unshrouded male header from the BERGSTIK® II series. It uses the industry-standard 0.100" (2.54 mm) pitch, making it a drop-in fit for any board laid out for a 0.100" header footprint. The contacts are square phosphor bronze pins with tin plating on both the mating surface and the solder tails, rated for 5 A per circuit. The housing is black UL94 V-0 polyamide, and the overall contact length is 1.238" (31.45 mm) — a long-pin version suited for through-hole soldering into a standard PCB.
What the Ratings Mean for the Build
The 5 A per-circuit rating is a signal-grade figure — fine for logic-level loads, low-current I/O, or control signals, but not a power rail. The 0.100" pitch limits the creepage between adjacent pins, so the 110 V rating is realistic for low-voltage signal paths, not mains-level isolation. The tin-on-tin contact interface is cost-effective but wears faster than gold under repeated mating; this header is best suited for a one-time build or a low-cycle interconnect where the connector is mated once and left alone. The unshrouded design means the pins are exposed — the mating receptacle must align squarely, and the board layout should keep adjacent components clear of the bare pins to avoid accidental shorts.
Sourcing and Lifecycle
The 87185-421HLF is listed as Active in production — no last-time-buy or end-of-life notice on record. There is no official replacement or cross-reference; the original part number is the correct BOM line item.