What is the difference between Trace Resistance and Trace Impedance?

 

While we always talk about the impedance of the PCB trace, resistance of the PCB trace is also an important parameter to consider.

Trace resistance depends on the cross-sectional area of a trace and it is more of resistive property of the trace. This something is like which can be measured by a multi-meter as we do for resistors. Trace resistance is to be considered across the frequencies. Signal loss in the trace conducting signal is due to the trace resistance.

Trace impedance is the sum of all the resistance and reactance components of the PCB trace. Trace impedance plays a crucial role as frequencies of the signals go higher. Trace impedance depends on:

• width of the PCB trace
• thickness of the PCB trace
• thickness of the dielectric
• PCB trace to reference plane distance