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Can anyone help with a reference design for a fully differential amplifier for a hydrophone (piezoceramic element)? It need to be differential input and differential output as signal needs to be transmitted over long lines. Thank you
can say more about the sensor? Do you have a datasheet of at least an equivalent circuit model? And what about the input signals which have to be amplified? Any specification?
Hhm, is a differential input stage actually needed? If so, why?
If the sensor needs to see a high input impedance, consider the diff. I/O circuit in section 9.1.5 in the OPA838 datasheet where I also included a discussion of CM stability issues - we had a similar application using this where the next stage was an FDA like the THS4551. In that complete signal chain, the high output CM noise from this first stage was rejected by the CM loop of the FDA - pretty cool actually.
If the sensor can see some R loading, consider just the FDA families directly.
And actually Traian, as I am recalling some ealier hydrophone work, it is sometimes the case they drive into a tuned network for narrowband gain. That would easier with the OPA838 approach where you still need to provide for input bias current to the V+ nodes.
