The TE Connectivity 120521-1 is a 64-position receptacle from the Free Height (FH) IEEE 1386, PMC series, designed for mezzanine board-stacking applications. The connector accepts mated stacking heights of 8mm, 9mm, or 10mm, which gives the board designer flexibility in setting the z-axis clearance between parallel PCBs. This is a surface-mount part, intended for reflow soldering.
Mated Stack Height and Board Clearance
The 120521-1 is rated for mated stacking heights of 8mm, 9mm, and 10mm. The height above board for this receptacle alone is 0.212" (5.38mm). When selecting the mating plug (the center-strip contact member of the Free Height series), the combined stack height determines the final clearance between the two PCBs. For a 10mm stack, the plug height above its own board is roughly 10mm minus the receptacle's 5.38mm, leaving about 4.62mm for the plug body. This dimension must be verified against the mating part's datasheet to ensure the full stack lands within the enclosure's z-height budget.
Comparison with the 1-120532-2 Plug
The 1-120532-2 is the mating plug for this receptacle, part of the same Free Height (FH) IEEE 1386, PMC series. It uses the same 0.039" (1.00mm) pitch and dual-row layout but carries 84 positions, not 64. Its height above board is 0.250" (6.35mm) versus the 120521-1's 0.212" (5.38mm). The 84-position count means it is wider than the 64-position receptacle, so the circuit count must match on both halves of the mezzanine connection. The plug is box-packaged rather than Tape & Reel. For a 64-circuit BOM, the 120521-1 receptacle mates with the 64-position variant of the plug, not the 84-position 1-120532-2.