stacking opa 861 buffer
Hi Gents,
Has anyone tried stacking the opa 861 buffer stage ? Am thinking of trying out a step up Avc passive pre amp but am worried that the buffer current might be insufficient. The Avc that Im looking at has a 5 times step up ratio, input impedance is 600 ohms & output 15k ohms.
Thanks in advance
I, honestly, did not, so this might not be the answer you were seeking, but I would check if you need higher driving capabilities at all. The OPA861 is a diamond structure, which is one of the most capable buffer architectures.
On the other side, if you are worried about the output impedance, it's 8 Ohm (typical) may indeed be compromised by the transformer ratio, but then again, you might want to double-check the overall interface equation.
As a side (but equally important) note, I do not like paralleling active, and even passive devices, unless really necessary.