Board-Stacking Fit for Tight Z-Height Budgets
The Hirose BM28B0.6-30DP/2-0.35V(53) is a 30-position header from the BM28 series, designed for board-to-board stacking where the vertical gap is the tightest constraint. Its 0.014" (0.35mm) pitch and 0.6mm mated stacking height put this in the ultra-fine-pitch, sub-1mm mezzanine class — think smartphone internals, wearable PCBs, or any assembly where every tenth of a millimetre of board spacing is allocated. The outer shroud contacts and 0.018" (0.46mm) height above board mean the header sits nearly flush with the PCB surface, so the mating receptacle determines the final stack height.
Pitch and Stacking — What the Numbers Mean for Layout
At 0.35mm pitch, the trace escape from these 30 positions (dual-row, so 15 per row) demands a high-density PCB fab — standard 0.5mm-pitch routing rules don't apply. The 0.6mm mated stacking height is the total gap between the two PCBs when the header mates with its matching BM28 receptacle; the header itself sits 0.46mm above the board, so the receptacle contributes the remaining 0.14mm. That's a near-contact stack, which keeps the interconnect short for signal integrity but leaves no room for stiffening ribs or alignment posts — the solder joints take the mechanical load.
Solder Retention and Mounting
Surface-mount only, no through-hole option. If you're planning to mate and unmate this connector more than a handful of times, the gold will wear through to the nickel underplate and contact resistance will drift.