TPA3144D2 THD+N Question

answer

Other Parts Discussed in Thread: TPA3144D2

Hi,

I have met a technical problem when debugging TPA3144D2.

I use APX525 and AUX0025 (two instruments) to test the board of TPA3144D2. The connection is as following:

I use the APX525 to analog output an sine signal and connect the output to TPA3144D2 board, then connect the output of TPA3144D2 to a 6ohm resister, connect the two pin of resister to AUX0025, and connect the output of AUX0025 to the analog input of APX525.

First, I tested the THD+N, the sine wave is 100 mVrms, 1KHz, the result is as following:

The THD+N Ratio is bigger than the datasheet shows:

Then I changed the filter capacitor of PVCC and AVCC from 100uF to 330uF, sine wave is 315mVrms, 1Khz, the result is as following:

Then I changed the input capacitor of LINP and LINN from 1uF to 2.2uF, changed the output 0ohm resister that connected to OUTPL and OUTNL to ferrite bead (BLM18PG121SN1), sine wave is 630mVrms, 1khz，the result is as following:

The THD+N results are much bigger than the datasheet. Could you kindly help with it?

over 7 years ago

0 Diego Melendez over 7 years ago

TI__Guru 57800 points

Hi, Terry,

My colleague will take a look to your questions and will get back to you as soon as possible.

Best Regards,

-Diego Meléndez López
Audio Applications Engineer

0 Peter Cao over 7 years ago in reply to Diego Melendez

TI__Expert 5000 points

Hi, Terry

I think you should also add a filter in APX525.

0 Peter Cao over 7 years ago in reply to Peter Cao

TI__Expert 5000 points

Try to use a 22kHz low pass filter and change the high pass filter to >10Hz.

The inductor or ferrite bead of the output filter also affect THD+N a lot.

0 answer over 7 years ago in reply to Peter Cao

TI__Intellectual 1735 points

Hi, Peter,

I have tested the TPA3144D2 and the results are as following:

First, I use the 200mVrms, no filter:

I get the result:

Then I add filter:

Then I change the sine wave to 630mVrms, no filter:

then I add filter:

When the sine wave is 200m Vrms, the THD+N reduced obviously, when the sine wave is 630m Vrms, the THD+N reduced little. It still a little far from the datasheet:

Output power is 5W (sine 630m Vrms). Could you kindly to see it?

Best Regards

Audio

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TPA3144D2 THD+N Question