Good late Friday afternoon to all,

I am trying to understand what happens to my impedance calculations when we
start going below 35 ohms. When I use Ultracad or do the calculations by
hand I get the following results:

Copper finished - .0014 (1 oz.) 

Dk - 3.5 (it is a flex)

h- .003

Line width to get 25 ohms (surface microstrip) - .007 to .008.

We wound up building this part with a line width of .016 and the TDR results
measured by both myself and my customer are 29-30 ohms.

When I use the calculator from Txline it says the line width should be .016.


 

Thanks in advance. Regards Steve Kelly

 

 

PFC Flexible Circuits Limited

Ph: (416) 750-8433

Fax: (416) 750-0016

Cell: (416) 577-8433

E-Mail: [log in to unmask]

 


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