OPA551: OPA 551 Gain

Hello,

This approach appears fine; however we would need more details to understand what exactly could be wrong.  Can you send a full schematic and a description of the problem, along with any data or scope plots you may have that show the problem?

Regards,
Mike

Final stage is not giving desired gain. The bias vol is +- 30 volt. The output should be greater than 16 V. But it is coming less than 2 V

Ok.  Again without any information, it is nearly impossible for us to help.  What is the load?

Hi Mike

load is 600 ohm

Regards

Ok - that shouldn't be a problem.  What frequency and amplitude are you trying to measure?

Hi Mike

frequency is 100hz to 7khz, amplitude is 16 Vrms

Hi Vinay,

Ok.  From everything I see that you've written so far, you should be able to get it to work.  I've included a sim. here to show that the OPA551 does indeed work with the circuit above.  I think the only way we make any progress here is if you can send your schematic, there must be something in the details that is causing the problem.

Mike

OPA551_Gain_of_17p6.TSC

Vinay,

One other thing - my sim. above just shows the output stage.  It could very well be the case that the loss of amplitude is coming from the filter.  Can you measure the output of filter blocks you have shown above and check if you really are getting unity gain in the passband of the filter?

Regards,
Mike