Why do we use 50 Ohm impedance on PCB?

[kattice]

Anybody know why we use 50 Ohm impedance trace on most of PCB?

Thanks,

 

[zeeshanzia84]

B/c most ICs and sources are designed for an output impedance of 50 Ohms, so we want to ensure impedance matching, so that there are no STANDING WAVES. Try to google out some article on "TRANSMISSION LINES".

HOPE THIS HELPS!

 

[kattice]

That is right. Most of ICs are designed for 50 Ohms impedance. But why these are designed for 50 Ohms? Is this due to IC's limitation? Or is this due to some historical reason?

 

[A.Anand Srinivasan]

try reading this article everything will be clear....