ENGINEERING ANSWER
For a fixed substrate and dielectric constant, a 75-ohm microstrip is narrower than a 50-ohm line. The narrower geometry can make etch variation and manufacturing limits more important.
What to decide before release
Check trace width, launch dimensions and the impedance of every connector and component in the path. A 75-ohm line connected to 50-ohm test equipment needs a deliberate measurement strategy; otherwise mismatch may dominate the observed result.
Checks to put in your design brief
- Calculate width for the released stackup
- Check minimum feature capability
- Document the measurement reference impedance
Important distinction
Changing trace width alone does not convert a complete 50-ohm circuit into a matched 75-ohm system.
Sources & basis
Material facts follow the cited source. Design checks are preliminary guidance, not supplier process instructions.