The Hirose BM28B0.6-30DS/2-0.35V(53) is a 30-position receptacle in the BM28 series, using a center strip contact arrangement across two rows. The 0.014" (0.35mm) pitch and 0.6mm mated stacking height place it in the ultra-fine-pitch, low-profile mezzanine class — designed for board-to-board interconnects where z-height is the tightest constraint, such as stacked PCBs in smartphones, wearables, or compact modules.
At 0.35mm pitch, the board footprint is dense — trace routing between pads requires a fine-line PCB capability. The height above board is 0.024" (0.61mm), and the mated stack height is 0.6mm, so the total clearance between the two PCBs after mating is just over half a millimetre. That means no components taller than 0.6mm can sit under the connector on either board. The 0.6mm mated height is the same across the BM28 series, so swapping position counts (30 vs 34) does not change the z-budget.
Comparison: 30-Position vs 34-Position Siblings
The BM28B0.6-30DS/2-0.35V(53) shares the same 0.35mm pitch, 0.61mm height above board, gold plating thickness, and solder retention feature with the 34-position BM28B0.6-34DS/2-0.35V(53). The only difference that drives selection is the position count: 30 circuits vs 34 circuits. If your BOM calls for 30 signal lines, this is the match; the 34-position variant adds four extra lines on the same footprint length, but the extra positions require a wider board edge allocation.