How to control and calculate your PCB Impedance?
You can't control your PCB Impedance if you don't know how to calculate it.Best Tech PCB manufacturing Engineer can help you calculate the Impedance in your boards,so you can send us your PCB files to get help from us,we are always here for you,but it may be better if you can understand how to calculate PCB Impedance,because lots of PCB designer and electronic designer ask us to help them to understand the knowledge of PCB Impedance calculation so that you can control the Impedance when they design their PC boards by themselves.
First,PCB Impedance formula is needed to explain better.
Zo=87Er+1.41−−−−−−−−√ln(5.98H0.8W+T)
Thanks for this PCB Impedance formula,and glad to see it so that we can know what Impedance is.But it is very difficult to understand for us to know how to control the Impedance when we design PCB or manufacture PCB.Read the information as below to get more help.
What's the influencing factors of PCB impedance?
As the PCB Impedance formula above,we know the Er,H,W and T will decided the value of Impedance on PC boards,but somebody may don't which mean.Er is dielectric constant,but how to confirm the value?Er is decided by the PCB core material,so you have to confirm the value of Er just when you can confirm your PCB core material,meanwhile the soldermask will affect the Impedance if you have strict requirements,so you can get help from us or your PCB supplier to get the more accurate information about PCB Impedance.Following list the variable of Impedance formula FYI.
| Variable |
Meaning |
| Er |
Value of dielectric constant of medium (PCB core Material) |
| H |
Height of Medium：For example,the thickness between two copper layers. |
| W |
Width of the target circuit line |
| T |
Thickness of the line(copper thickness) |
The software/tooling for Impedance calculation of PCB
Impedance calculation on PCB should be more convenient and swift,everybody know that we calculate Impedance as the formula above will be nightmare,when we have to debug the Impedance by changing line width or thickness of PCB core material,which will be very very hard work if we calculate by hand even using computer.Now,here will recommend software/tooling to help you calculate the Impedance on your PC boards.Which is very useful for your PCB design job.
It is Polar_Si9000 and which is very popular for PCB Impedance calculation.you can download or search more information from the website of Polar.BTW,in the model above,there are W1 and W2,W1 should be the trace width that you design in your PCB files,but W2 is a little smaller than W1,for 1 OZ copper ,W1-W2=1 mil,Others model,pls contact PCB manufacturer to confirm all the parameters just in case.
You also can visit our website for more PCB knowledge,meanwhile we are always here to help you to calculate the Impedance on your PCB boards,so don't hesitate to send us your PCB files to get help about PCB Impedance control.
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