DF40C-100DP-0.4V(51) from Hirose Electric Co Ltd is a surface-mount rectangular connector plug in the DF40 family, suited for compact board-to-board interconnect designs where high contact density and reliable mating are important. With 100 positions, outer shroud construction, gold contacts, and tape-and-reel packaging for automated assembly, it fits well in portable electronics, embedded control boards, industrial modules, communications hardware, and other space-constrained systems. Engineers typically select parts in this category for stable signal routing, miniaturized layouts, and repeatable SMT processing. Based on the provided data, this part carries an Unknown lifecycle status, so design teams should confirm current manufacturer status before committing to long production programs. Supply is marked Limited and estimated production lead time is 25 weeks, which suggests some procurement planning is advisable. RoHS compliance information is not available in the supplied specifications, so engineers should verify RoHS and related material declarations directly from Hirose documentation or authorized distribution sources.