TLV320AIC3104-Q1: TLV320AIC3104-Q1

Sunil BK

Hi Team,

I am working the above device, finding the SNR and THD values with Sine wave input (984.375Hz) input signal generating through AWG with 448KHz Sampling frequency.

In the Test Input signal pass through the Input Buffer, Mixer, PGA and then Map to Low power output pins through register setting.

We could read SNR values around 72dB and noise floor at -80dB.

Hardware detail: We have on board filter at Low power output pins with 10K resistor connected. with this resistor value we getting SNR 72dB, for experiment purpose change to 5K instead of 10K then we got 89dB SNR and noise floor at -110dB . please find the attached PPT for reference and let us know whether placing 5K resistor is allowed.

TI_PPT.pptx

Thanks & Regards,

Sunil BK

over 5 years ago

0 Steve-Wilson over 5 years ago

TI__Mastermind 30030 points

Sunil,

The SNR is measured with the following conditions: A-weighted, fS = 48 ksps, 0-dB PGA gain, inputs ac-shorted to ground. Is your measurement A-Weighted?

Your external resistor experiment is reproducing the results in this application report which shows that there is out of band noise, and if the user wants to reduce the noise using a passive RC filter is very effective.

best regards,

-Steve Wilson

0 Sunil BK over 5 years ago in reply to Steve-Wilson

Prodigy 125 points

Hi Steve,

Thanks for the information, yes we are taking A-Weighted output. Please find the attached schematic for your reference.

Regards,

Sunil BK

0 Steve-Wilson over 5 years ago in reply to Sunil BK

TI__Mastermind 30030 points

Sunil,

are you measuring the Differential Low power output? or are you measuring the low power outputs Single ended?

Are you also routing your DAC to the same output? or is the DAC powered down? the proper way to measure this would be to look at the Digital output. I wouldn't expect the output mixer to have a large effect on the SNR, but to be sure the DACs should be powered down. If the DAC is also routed to the output that might impact the SNR.

When we perform this test, we use the Audio precision analyzer, the AP looks directly at the digital audio.

best regards,
-Steve Wilson

0 Sunil BK over 5 years ago in reply to Steve-Wilson

Prodigy 125 points

Hi Steve,
We are measuring the Differential Low power output and in other test measuring single ended High power output.

DAC routing to Low or High power outputs are not done and DAC is power down. PGA routing to Low power output done and and powered on Low power outputs.

Thanks & Regards,
Sunil BK