Via selection for diffrent signals

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ramalakshmi

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Hi,

Can anyone help me how to select the Via hole size.right now we are using 40mil pad with 23mil drill.
in IPC2221A it was mentioned to take 0.3mm drill hole to vias for reducing the inductance at highfrequencies.If any one explain me what are the things that will effect by changing the via size and its hole.

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Rama Lakshmi.Ch
 

Because the inductance of via is increased as the decreasing drill diameter, so the series impedance is increased, and loss through the via also inceeases.
 

ramalakshmi said:
Hi,
If any one explain me what are the things that will effect by changing the via size and its hole.
Rama Lakshmi.Ch
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As frequency increases and signal rise time reduces, via causes impedance discontinuities resulting in signal reflections and hence deterioration of signal integrity and system performance.
 

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