TPA6111A2: Non-inverting configuration

Gavin L

Part Number: TPA6111A2

Hi,

I have a mono-to-stereo amplifier application with a high source impedance. The TPA6111A2 in inverting configuration is loading the source too much, so I was wondering if I could configure it for non-inverting operation by using the BYPASS pin as an input (AC-coupled, of course). Is there any reason I shouldn't do this? I don't need gain < 1, and I can ensure that Ci << Cbyp so that it doesn't affect start-up.

Crude schematic below:

Thanks!

Gavin

over 3 years ago

0 Luis Fernando Rodriguez S. over 3 years ago

TI__Guru* 84915 points

Hi, Gavin,

Welcome to E2E and thank you for your interest in our products!

Could you share your schematic file again, please? It seem that it couldn't be fully uploaded in this e2e thread.

Thank you.

Best regards,
Luis Fernando Rodríguez S.

0 Gavin L over 3 years ago in reply to Luis Fernando Rodriguez S.

Prodigy 40 points

0 Luis Fernando Rodriguez S. over 3 years ago in reply to Gavin L

TI__Guru* 84915 points

Hi, Gavin,

Unfortunately we don't recommend this kind of use for the Bypass pin. This kind of connection may affect the midrail generation circuit and the TPA6111A2 may result in a misbehavior. So, we recommend to connect this bypass pin with a capacitor to GND as shown in the typical circuits of the datasheet.

Best regards,
Luis Fernando Rodríguez S.

0 Gavin L over 3 years ago in reply to Luis Fernando Rodriguez S.

Prodigy 40 points

Hi Luis,

What sort of problems might you anticipate? This looks like a fairly standard single-supply non-inverting op-amp configuration. Is there something more complicated going on?

Thanks,
Gavin

0 Luis Fernando Rodriguez S. over 3 years ago in reply to Gavin L

TI__Guru* 84915 points

Hi, Gavin,

We have seen cases where the output common-mode level is modified due to the misusage of the bypass pin, resulting in clipping issues with low gains. We recommend to follow the typical circuits recommendations in order to avoid this kind of conflicts.

Best regards,
Luis Fernando Rodríguez S.

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TPA6111A2: Non-inverting configuration