Board-stacking selection: 140 I/O at 0.80 mm pitch
The TE 5177983-6 is a 140-position receptacle from the Free Height (FH) series, built for dense mezzanine board stacking. The 0.80 mm pitch packs the I/O count into a compact footprint — the sort of density you need when routing a hundred-plus differential pairs between two parallel PCBs. It mates with the matching FH plug to achieve stack heights of 5mm, 6mm, 7mm, or 8mm, so the same receptacle can serve multiple board-spacing designs by swapping the plug height. The outer shroud contacts shield the signal pins and guide the mate, with an integral board guide on the receptacle to align the boards during assembly.
What the 0.80 mm pitch and 140 positions mean for the board layout
At 0.80 mm pitch, the footprint is tight — the via field and trace escape for 140 positions (70 per row) need careful fan-out, typically with micro-vias or buried vias in a multi-layer board.