TAS5760M: Analog gain tolerance

Hi Mimura

thanks for your question.

it seems like clipping happened in your situation.

what is your pvdd voltage?

have you set any soft clipper in your circuit.(you can refer section 8.4.1.3 in the datasheet.)

thanks.

jesse

Hi jesse

Thanks for your reply.

PVDD is 24V.
Soft clipper is not set.

Below are the settings.

SFT_CLIP Pin Voltage[V]: GVDD
Resistor to GND [kΩ]: Open
Resistor to GVDD [kΩ]: 0Ω

THD+N is also less than 0.1%.

Is there any other reason?

Also, please answer the following.

1. What causes the output to be smaller than the calculated value?
2. What are the factors that cause the output to fluctuate?
3. What is the range of output variation?

Best Regards,
S. Miura

Hi Miura

Answers are as below:

1. What causes the output to be smaller than the calculated value?

usually, it should not have such big difference except the clipping.
2. What are the factors that cause the output to fluctuate?

i don't think your output fluctuate is because chip variance, it should be somewhere configuration has problem.
3. What is the range of output variation?

usually, output variation should be less than 0.5dB. you problem should not be caused by chip variation.

can you share me you schematic, also if possible, the register value is also very helpful.

thanks.

jesse

Hi Jesse

Thank you for your reply.

1. What causes the output to be smaller than the calculated value?

　Usually, it should not have such a big difference except the clipping.

　⇒Is my calculated value (7.16Vrms) correct?

3. What is the range of output variation?

　Usually, output variation should be less than 0.5dB.

　⇒Is the output variation of the TAS5760 within ±0.5dB?
　　When I checked several additional boards, there were some that output 7.3Vrms or more.
　　So I don't think it's a Clipper factor.

I would like to send you the schematic and register settings, so can I email you directly?

Best Regards,
S. Miura

Hi Miura

1. yes, your calculation is correct.

2. you mean with same configuration, output of some other board is close with your calculation, some boards don't? 

sure, you can send me directly by below email.

jesse-ji@ti.com

thanks.

jesse

Hi jesse

1. yes, your calculation is correct.

　⇒If the variation is ±0.5dB, is the output range min 6.78V typ 7.16V max 7.58V?

2. you mean with same configuration, output of some other board is close with your calculation, some boards don't?

　⇒That's right. Overall, there is a tendency to be smaller than the calculated value, but one PCB was found to be larger than the calculated value.
　　I just sent you an email with the results of measuring eight boards with the same circuit as a file with register settings and circuit diagrams.

Please confirm.

Best Regards,
S. Miura