Per Unit Length Trace resistance?

[kato]

hi Tom,

Is there a calculator, or is it even a valid question, to estimate the trace impedance per unit length? I am not looking for the PCB trace's characteristics impedance.

In particular, I am designing a power management system that needs to account for IR drop along a trace from the supply to the device it is powering. I don't want to constrain myself by guardbanding the 'R' value too much.

Thanks
K

[kato]

The board will be standard FR4. I assume I would need to look at parameters such as:
Trace width = 6 mils.
Trace length = 4 inches.
Copper weight = 1 oz.

[Tom]

kato,

Polar Instruments has a great "Free" Track Resistance Calculator called "TRC100".

Go to this website and scroll down to the FREE PCB Track Resistance Calculator. TRC100

http://www.polarinstruments.com/

[kato]

There are so many small tools available! Thanks for the link.

- K