Is This circut suitable for an OPA541?

bigmike216 · 28th April 2005, 05:23 AM

Attatched a schematic.. is it suitable?

Would the same curcut work with the opa549 and 548, provided I made the proper adjustments to the pin numbers of the chip in the schematic?

macboy · 28th April 2005, 01:34 PM

Looks like you have a gain of 22, which is way too high for the OPA541. Unless this is a subwoofer amp, reduce the gain, or your high frequency response will suffer. If you need more gain, add a simple pre-amp stage with a good quality opamp.

bigmike216 · 28th April 2005, 03:05 PM

what is a suitable gain?

macboy · 28th April 2005, 03:38 PM

The gain-bandwidth product of the OPA541 is 1.6 MHz. In order to keep the audio band frequency response of the amp clear of the effects (in both amplitude and phase) of limited bandwidth, I would recommend keeping the bandwith above 100 kHz. That means that the maximum gain should be around 16. The OPA549 is even more restricted with its GBP of 0.9 MHz. The National LMxxxx chips generally have a much higher GBP (e.g. 8 MHz for LM3886) so they can be run at higher gain than these TI chips.

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28th April 2005, 01:34 PM	#2
macboy diyAudio Member Join Date: Oct 2003 Location: Ottawa, Canada	Looks like you have a gain of 22, which is way too high for the OPA541. Unless this is a subwoofer amp, reduce the gain, or your high frequency response will suffer. If you need more gain, add a simple pre-amp stage with a good quality opamp.

28th April 2005, 03:05 PM	#3
bigmike216 diyAudio Member Join Date: Jul 2004 Location: BC, Canada	what is a suitable gain?

28th April 2005, 03:38 PM	#4
macboy diyAudio Member Join Date: Oct 2003 Location: Ottawa, Canada	The gain-bandwidth product of the OPA541 is 1.6 MHz. In order to keep the audio band frequency response of the amp clear of the effects (in both amplitude and phase) of limited bandwidth, I would recommend keeping the bandwith above 100 kHz. That means that the maximum gain should be around 16. The OPA549 is even more restricted with its GBP of 0.9 MHz. The National LMxxxx chips generally have a much higher GBP (e.g. 8 MHz for LM3886) so they can be run at higher gain than these TI chips.