I'm building a physics device called and MWPC which requires that a sense wire be held at a high potential (~1800 V) and that a small signal (~10 uA) be amplified from it through a TIA and then fed into an ADC as a differential pair. I've been trying to use a blocking capacitor to stop the 1800 V DC and pass the small transient signal to the amplifier and then use an AD8476 or similar IC to convert the single ended output from the amplifier to a differential signal for the ADC. Unfortunately, the blocking capacitor seems to be creating instabilities in the TIA circuit. My question is whether I could just set the ground on the TIA and the AD8476 to the 1800 V of the sense wire, have the power rails at an appropriate level relative to the "new" ground (~1795 V. and 1805 V.) and eliminate the blocking capacitor? Would the differential signal fry the ADC which is grounded at the "original" ground? I seem to recall the differential signals are not relative to any external voltage reference, but would the AD8476 isolate them well enough? What parameter on a data sheet would describe this isolation?
Thanks.
Thanks.