Re: PCB Layout...loop areas?

bill.sloman@xxxxxxxx wrote: 
bigschlong@xxxxxxxxx wrote:

Hi!

I've been reading some PCB layout design documens. When they say loop
areas, are they only referring to loops on one side of the PCB?

I looked at my design and noticed that there is a loop area on the Top
side. If I re-route some of the wires to the bottom side, will this
eliminate the loop area?



The "loop area" is interesting in as far as it is a measure of how much
magnetic flux is linked to the loop - it is another way of saying "what
is the mutual inductance between this conducting loop (secondary
winding) and the various current-carrying loops on and around the board
(primary windings) ta might excite it."

Any connection that completes the loop - on either side of the board -
has to be taken into account.


thats only part of the story.

for a start, the loop is an antenna, so its is also quite capable of transmitting as well as receiving - IOW it can be the "exciting" loop.

then of course the inductance of the loop can (and usually does) have a deleterious effect on the behaviour of the associated circuit.

good pcb layout can be summarised in 6 words:

Current Flows In Loops. Minimise Them.

Cheers
Terry
.