What this 2-position MTA-100 header does
The 640456-2 is a vertical through-hole header from TE's MTA-100 series, 2 positions on 0.100" (2.54mm) pitch, designed for board-to-cable/wire connections. The shrouded 1-wall housing and friction lock keep the mating plug seated against vibration and cable pull. Tin-on-tin contacts suit moderate mating cycles in general-purpose equipment.
Pitch and footprint for board layout
The 0.140" (3.56mm) solder tail length suits standard 1.6mm-thick PCBs — the post protrudes enough for a reliable fillet without bottoming out in the plated hole. Total contact length from the mating face to the solder tip is 0.535" (13.59mm), with 0.295" (7.49mm) of that dedicated to the mating interface for a secure connection with the receptacle.