The 6SL3520-1XD00-7AB0 is a D-connector SINAMICS G115D with the 1X catalog prefix — 0.75 kW in FSA frame (380 × 156 × 129 mm, natural convection) with AB0 Standard I/O. It is the 1X-prefix parallel to 0XD00 (0X-prefix D-connector at the same power) — same D-connector interface, same FSA frame, same 2.2 A HO rating at 380–480 V three-phase. The "1" vs "0" prefix is commercial catalog organization. Compatible with IE2/IE3/IE4 motors across 0–550 Hz, IP65 sealed.

1XD00 vs 0XD00 — any difference?

None electrically or mechanically. 1XD00 (1X catalog prefix) and 0XD00 (0X catalog prefix) are parallel catalog codes for the same 0.75 kW FSA D-connector hardware. Both deliver 2.2 A HO at 380–480 V, both use the identical D-connector and FSA frame. This is the same parallel-catalog pattern seen across all G115D connector families: 1XB/0XB for B-connector, 1XC/0XC for C-connector, and now 1XD/0XD for D-connector. Choose whichever PN is available from distribution — the drive hardware is identical.