Impedance correlation report requirements
Application Note AP186 

Impedance correlation requirements

Occasionally, measured and predicted impedance do not correlate within expected measurement. Polar offers a professional commercial correlation service to help determine the root cause of the variation. Before a correlation study can start we need to receive the following physical and technical documentation. Correlation services are chargeable, and are available for correlation questions arising on impedance controlled structures modelled with Si8000m and measured with the CITS880.

 Requirement  Supplied?

1. All data must be clearly labelled and supplied. It must be clearly marked which track on a coupon or Gerber artwork is the one to be investigated. If more than 1 problem track is supplied, it must be clearly marked which data refers to which track. (Associated notes and supporting information also need to be provided in English)


2. What is the design stackup? Preferably a Speedstack (.sci ) file. You must include expected layer stackup, manufacturer & material used & material properties. A material data sheet would be useful if using an unusual or regional specific material. Clearly indicate the problem track(s).


3. Gerber files from every copper layer of the stackup – not just the problem layer.


4. NC drilling information with the Gerber (so we can view the Gerber layer interconnects)


5. CITS waveform files (.cvf) of problem track(s)


6. CITS .cif file


7. At least 3 physical samples of each track to be investigated. Permission to destructively test sample, e.g. for microsection or other test as required. At the end of the investigation the sample will usually not be returned, so indicate if samples are expected to be returned.


8.What impedance calculation was performed with what numbers? Include .si8 file or .sci file with impedance data.


9. Microsection pictures and data if available, clearly labelled from which track the section was taken. You must include the CITS waveform file (.cvf) of this track before it was sectioned.


10. Date of last CITs calibration – model and serial number.


11. All electronic data must be zipped and emailed in a file clearly named ""


For further correlation study information and pricing please talk to your regional Polar office.