Author Topic: PCB Material Thickness  (Read 3915 times)

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Online joniengr081Topic starter

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PCB Material Thickness
« on: November 26, 2023, 04:43:29 pm »
I was searching for low loss high speed PCB material and found the datasheet of the following materials.

1-   MEGTRON6 Normal glass cloth: R-5775(K)/R-5775(G): Dk = 3.62 @ 13GHz
2-   MEGTRON6 Low Dk glass cloth: R-5775(N): Dk = 3.34 @ 13GHz

The above dielectric constant values Dk representing the Core material. What are the dielectric constants Dk for Prepregs R-5670(K)/ R-5670(N)/ R-5670(G) ?
In which thickness (glass cloth style) these Core and Prepreg are available ?  Are they available in 106, 1080, 2116 and 7628 ? The reason of asking this question is, we need to specify the thickness of Core and Dielectric in the Stackup Editor of the PCB Design Tool along with the dielectric constant value Dk.


Offline ViaTech

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Re: PCB Material Thickness
« Reply #1 on: December 22, 2023, 11:50:48 am »
Dk for Prepregs R-5670(K)/ R-5670(N)/ R-5670(G)
They are available for 1035, 1078, 2013 and 2116 types.
DK for 1GHZ is as follows:
Type 1035--60um: 3.20; 68um: 3.16; 74um: 3.13;
Type 1078--77um: 3.26; 89um: 3.22; 104um: 3.17; 118um: 3.13;
Type 2013--98um: 3.40; 106um: 3.37;
Type:2116--125um: 3.40; 132um: 3.37.
But we need to know the different resin content. It is better to have the datasheet from Panasonic.
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Offline free_electron

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Re: PCB Material Thickness
« Reply #2 on: December 31, 2023, 06:44:00 pm »
a quick word. dk is given for a specific frequency band. use the one that matches your signals ! using the 6ghz dk with a 500 MHz signal is nonsense
be aware of the weave and resin content. loose weave is very harsh on signal integrity. every time you leave the glass bundle you have a discontinuity.
this is especially important if you have differential pairs. one trace may be over glass, the other over resin causing a huge delta in impedance.
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