Author Topic: Lower dielectric constant in PCB layout  (Read 1877 times)

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Offline joniengr081Topic starter

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Lower dielectric constant in PCB layout
« on: June 29, 2023, 08:27:01 am »
Hi,

What are the advantages of using lower dielectric constant in PCB layout. Is that true that having lower dielectric constant in the stack up will have lower cross talk ? And for PCB involving high speed signals, lower dielectric constant is better ? What are the limitations of FR4 ? 
 

Offline thm_w

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Offline TimFox

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Re: Lower dielectric constant in PCB layout
« Reply #2 on: June 29, 2023, 09:43:43 pm »
All other things being equal (i.e., dimensions) a lower dielectric constant in the insulation between conductor and ground in a microstrip (or other transmission line geometry), gives less capacitance per unit length (inductance remains the same), and that gives a higher characteristic impedance and faster speed.  The actual equations are not as simple as for a coaxial line.
An introduction:  https://www.analog.com/media/en/training-seminars/tutorials/mt-094.pdf
« Last Edit: June 29, 2023, 09:52:03 pm by TimFox »
 


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