Impedance test point

[Kick]

hi,

What is mean by impedance test point?

our PCB assembly team asked this question. Is it for measuring board Impedance? If I add a via,where I should connect this Via for measuring Impedance?

Thanks

 

[senilicus]

Have a look at https://www.polarinstruments.com/support/cits/AP8502.html


regards, Charles

 

[FvM]

PCBs may include test structures for impedance-controlled manufacturing. These are transmission lines of some length, either embedded or micro strip lines, usually 50 ohms with test pads suitable for a low reflection connection of a TDR test instrument.

The measurements are primarily made by the PCB manufacturer to tune process parameters. The test structure layout has to be agreed before finishing the PCB design, there are IPC and vendor specific standards (e.g. from Polar Instruments) for it, if I remember right.

 

[Kick]

Thanks for your reply.

Our board is already fabricated and now assembly work is going on. I did not add any test point for Impedance,but there is a smd pad of feedline. Is it fine for measurement???