Does anybody bother useing a guard ring on op amps

[6666]

Over the years I've considered using guard rings on the inputs of op amps in mainly PI detectors, but never really bothered with them although I have seen recommendations to use them on the Baracuda, does anybody bother to use them ?

[waltr]

I did not put guard rings on the op-amp inputs when laying out the PCB for my Hammer Head II- mod.
I do use them when laying out PCB's at work on op-amps with very high input impedance to reduce leakage and capacitive coupling. I would think that these should help on the JFET/CMOS op-amps we use for integrators,

[Skippy]

Ive used guard-rings on other (non-MD) electronics equipment. I recommend you read up on them, and understand what they do and how they do it. Then you'll be in a better position to determine whether it's needed or not. It seems plenty of people have a poor understanding of their function, and hence put them round the wrong part of the circuit, join them up to inappropriate points of the circuit etc.

I'll try and find links to manufacturers app-notes on the subject.

[waltr]

I agree Skippy. If not used correctly they can make things worse.

As to the diagram posted above, this is not the complete picture. As any components that are connected to the same Node, like a resistor. The end of the resistor connected to the op-amp input must also be encircled with the guard trace.
Same links:
https://en.wikipedia.org/wiki/Driven_guard
http://www.linear.com/solutions/1853

Skippy may have other links to tech articles.

Another PCB layout consideration is a solid 'ground plane' to provide:
1- a Low impedance reference to op-amps.
2- a low impedance current return path for power and bypass caps.
3- helps reduce EMI into other parts of the circuit and from radiating.

[Davor]

The only place you may need a guard ring is a SAT circuit, simply because it is floating. There usually are the ways to reduce impedance, and you don't need a guard ring.