0.6mm Mezzanine Stack — BM28 Header
The Hirose BM28B0.6-20DP/2-0.35V(53) is a 20-position header from the BM28 series, designed for board-to-board stacking at a mated height of 0.6mm. The 0.014" (0.35mm) pitch and dual-row layout pack 20 outer shroud contacts into a footprint that fits tight mezzanine gaps in compact handheld or portable electronics.
20 vs 24 Positions — Same Stack, Different Circuit Count
The BM28 series offers this 20-position header alongside a 24-position variant (BM28B0.6-24DP/2-0.35V(53)) at the same 0.35mm pitch and 0.6mm stacking height. The decision between them comes down to the number of signal or power lines the board stack needs to route — 20 circuits vs 24 circuits, with no change to the board-to-board gap or footprint width. If your BOM calls for 20 positions, this is the match; the 24-position sibling adds four more lines without altering the vertical clearance.
Surface Mount with Solder Retention
The 0.018" (0.46mm) height above board keeps the profile low, and the 0.6mm mated stack height is the critical dimension for the mezzanine gap: make sure the opposing receptacle and any components on the underside of the top board clear this height. The 0.35mm pitch demands careful PCB routing — trace widths and spaces must match the tight pad layout.