03-05-2013, 07:56 PM
(03-05-2013, 08:54 AM)nickds1 Wrote: As an aside, with the overall unit at nominal input impedance of around 10Mohms and with the CA3140s having an extremely high input impedance of 1.5Tohms, it might be a good idea not to use sockets for the opamps and to use a conformal layer on both sides of the PCB to prevent moisture ingress and leakage...
Another possibility is to use individual poles from a (turned pin) socket and a guard ring on the PCB to minimise leakage.
See http://www.ti.com/ww/en/bobpease/assets/...om_rap.pdf page 46 (!19.7MB download)
Jim
