TPA6120A2: Harmonics observed at output

Jagadish Reddy putta

Part Number: TPA6120A2

Tool/software:

Hi,

We are using TPA6120A2 in our design, when we are giving sine wave (1KHz, 100mVrms) input to TPA6120A2 at HDPN+ and HDPN- from the analyzer and observed that there are harmonics at output signal name is HDPN_OUT. the FFT signals and scope signals attached in images these signals are captured at HDPN_OUT. the Schematic diagram i have copied in the attachement for your reference. Please ignore RIN+ and RIN- circuit as its not used at present. only consider LIN+ (HDPN+), LIN- (HDPN-) and LOUT (HDPN_OUT).

11 days ago

0 Alec Saebeler 10 days ago

TI__Mastermind 23049 points

Hello Jagadish,

I will look over these harmonic occurrences and provide a response back to you with my recommendations.

Can you confirm for me what is loading the TPA6120A2 output after the 10-Ohm series resistors?

Best,

Alec

0 Jagadish Reddy putta 10 days ago in reply to Alec Saebeler

Prodigy 85 points

Hi Alec Saebeler,

The Headset (Avionic Head set which have resistance around 360 Ohm) is connected after 10 Ohm resistor.

Thanks & Regards,

Jagadish.

0 Alec Saebeler 9 days ago in reply to Jagadish Reddy putta

TI__Mastermind 23049 points

Hello Jagadish,

Thank you for sharing more information on the headset impedance.

There are considerations for using this device, TPA6120A2, in single-supply configuration. It is not recommended and not the intended design use-case. To use single-supply, DC-blocking capacitors and correct biasing of the inputs to midrail (input common mode set to Vcc / 2) is required to prevent large DC current flow, which would affect performance.

I will examine any recommendations or support I can provide to reduce the observed harmonics. In addition the the device datasheet, the EVM user's guide also has useful design guidance.

Best,

Alec

0 Jagadish Reddy putta 9 days ago in reply to Alec Saebeler

Prodigy 85 points

Hi Alec,

Sure, We will wait for your recommendations.

Thanks & Regards,

Jagadish.

0 Alec Saebeler 8 days ago in reply to Jagadish Reddy putta

TI__Mastermind 23049 points

Hello Jagadish,

I will share the updates once I have them. Thank you.

Best,

Alec

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TPA6120A2: Harmonics observed at output