There are a lot of PCB trance impedance calculation tool available on internet, for example : http://www.eeweb.com/toolbox/microstrip-impedance
Trace impedance can be calculated by entering parameters "Trace Thickness", "Substrate Height", "Trace Width",and "Substrate Dielectric", but not the length of the trace.
My questions :
- Does the above calculation calculate "characteristic impedance", not the real trace resistance ?
- Do I need to concern trace resistance during PCB design ? For example, is there any performance concern to send a 100MHz clock through a trace as long as 10cm, compare to only 1cm ? If so, is there any calculation tool to for the trace resistance ?
Thanks a lot.