TPA6211A1: Output noise level in the shutdown mode.

Hi, Jan,

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

Effectively, the output of the TPA6211A1 is placed in high-impedance in shutdown mode. So, in order to have a low noise level on the speaker output, it is important to keep the layout designed to reduce external noise events such EMI or on-board noise. The device by itself won't generate high noise content. So, it will depend more of the layout design.

Please let me know if you have additional questions or comments on this.

Best regards,
Luis Fernando Rodríguez S.

Hello Luis,

thank you for the fast feedback. From my understanding I need to take care on a low resistive path at the outputs,

if the device is in HiZ mode, even if both outputs are connect together via a 7 OHM resistor ? Any suggestions

how to do this without using a switch ? Can I place in general e.g. a 1k resistor on each output to GND ? This would

drawn some additional current from the supply but as my signals are small it not matters that much.

Thank you, best regards

Jan

Hi, Jan,

I think an additional external array is not necessary for this Class-AB device. The idle channel noise of this device (device under normal operation but both analog inputs AC-coupled to GND) is around 15uVrms. This noise level decreases during the shutdown mode.

If you are interested in reducing the output noise still more, I would recommend to reduce the power supply ripple with additional capacitors (10uF and 0.1uF capacitors would help) and create a layout design to reduce noise from other devices in the board. Usually, a good practice is separate the amplifier ground plane from the rest of ground planes in the board and then join them with 0-ohm resistors or PCB traces.

The device by itself won't generate too much noise, especially during shutdown mode.

I hope this helps you! Please let me know if you have additional questions or comments on this.

Best regards,
Luis Fernando Rodríguez S.