TL972: TL972IDGKR high noise problem

Jim Tsai

Expert 4470 points

Part Number: TL972

Hi team,

Customer feedback the noise of TL972IDGKR is too high.

Below is schematic, could you please help to check which circuit we can adjust to reduce noise, thanks.

Application: Microphone

over 4 years ago

0 Luis Fernando Rodriguez S. over 4 years ago

TI__Guru* 84915 points

Hi, Jim,

Some questions about this noise issue. Could the customer verify if the noise level can also be measured at the power supplies pins? Are there more devices on the board with this noise problem?

Best regards,
Luis Fernando Rodríguez S.

0 Jim Tsai over 4 years ago in reply to Luis Fernando Rodriguez S.

TI__Expert 4470 points

Hi Luis,

Customer try to remove TL972IDGKR circuit and connect MEMS to ADC directly, SNR increase from 66dB to 68.1dB.

Please refer to complete schematic.

0 Jim Tsai over 4 years ago in reply to Jim Tsai

TI__Expert 4470 points

Hi Luis,

Correct schematic

0 Luis Fernando Rodriguez S. over 4 years ago in reply to Jim Tsai

TI__Guru* 84915 points

Hi, Jim,

Thank you for providing additional information on this.

Do you know if the power supplies of the TL972 have ripple or noise issues? I mean, could the customer try to increase the power pins capacitance? In addition, could the customer try to remove the output capacitors C320 and C321?

Please let me know if he has additional observations on this.

Best regards,
Luis Fernando Rodríguez S.

0 Luis Fernando Rodriguez S. over 4 years ago in reply to Luis Fernando Rodriguez S.

TI__Guru* 84915 points

Hi, Jim,

Excuse me, do you have a feedback on this?

Please let me know if you have any additional question or comments.

Thank you.

Best regards,
Luis Fernando Rodríguez S.

0 Jim Tsai over 4 years ago in reply to Luis Fernando Rodriguez S.

TI__Expert 4470 points

Hi,

So far no more question, thanks.

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TL972: TL972IDGKR high noise problem