[sdiy] Buffer feedback loop vs. PCB layout

[Justin Owen]

Apologies for the basics/fundamentals question - I did ask this on another forum but I didn't get a great answer (possibly down to my original explanation...) - so I thought I'd try here as well...

I have a PCB layout which comprises 2x different boards connected by a hardware connection.

http://www.sdiy.org/juz/feedback_loop_01.png

1) This simplified diagram represents the physical layout. A buffer output on PCB1 connects to an inverting op-amp input on PCB2 via an inter-board connector (the blue trace). 

2) Is essentially what the circuit 'sees' - a long trace from the output of the buffer to the input of the inverting op-amp.

3) This is what I'm worried about though - as far as the circuit is concerned - it's not just one trace from output to input - it's also - potentially(?) -  a long, extended feedback path/loop that travels all the way from PCB1 to PCB2 and back again.

That strikes me as not a very good PCB layout decision - it's basically a trace that is going to be way longer than it needs to be (OK - we're talking cm IRL - but still). Is that a correct assessment in regards to the layout?

So - my questions is - if this is correct and is potentially a problem - how do I solve it. How do I constrain the feedback path to the shortest possible area and ensure that only a single trace is travelling between boards - not a whole feedback loop.

My original idea was to put some sort of small value resistor after the output of the buffer - is that a contender?

Thanks,