Building a master-slave amp to drive a piezoelectric driver for a sonoluminescence experiment. Having a problem with the amplification.
The rails are at +/- 45 V (sorted that problem out, thanks to all who helped). Straightforward design from the data sheet of the OPA445 (45 V) op amp, with capacitive stabilization added in.
And the actual circuit I'm using. The buffer is necessary because the cheap frequency source will feed back if the input impedance isn't very high. All op-amps have trimmer pots attached per the data sheet's instructions, and have been properly nulled.
Circuit is driven around 25 kHz, don't think that is a problem for this chip and circuit - it's designed to drive piezos around those frequencies. At low outputs, it seems to work fine. But once the output voltage between the master and the slave goes to about 70 V peak to peak, increasing the input doesn't increase the output, it just clips at the top of the waveform. I can take some pics of the o-scope output if that would help. As far as I can tell, the output is symmetric to ground (until the clipping starts.)
Any help or info appreciated, will answer any questions I can, but will be on the road over the weekend. Thanks in advance.