Part Number: TLV320AIC3204
Hello, TI Experts,
Our customer sent us a question about TLV320AIC3204's IN1 channel cannot input the input signal.
We have done these tests:
1.delet the components connected to the IN1 Channel, not make sense
2. set the gain between input to ADC to 0dB,then analyse the ADC‘s data by recording on customer's computer,we found ADC's output I2S is strange.Its DC reference level is not 0V,but offset to the negative end.
When set the PGA gain to 0dB,dc offset is -48dBV(around 4mV);Then increase PGA gain,The reference signal move downward;
When set the PGA gain to the max 47.5dB，the signal reference will be -24dBV(around 0.06V)
3. We change the channel to IN2/IN3,the offset is much smaller.
The Question Is：
Why is IN1 different from IN2/IN3?
Our Customer has designed to use IN1,if change to IN2/IN3,It may spend much more time to redesign.
Do we have any methods to solve the IN1 problem？
Look foward to your kindly reply,Thank you ~~
In reply to Luis Fernando Rodríguez S.:
We do the test with AIC3204EVM and it's GUI, using the recording setting recommended by the GUI, just change MIC PGA Gain and Mic input channel. The IIS is analyzed by PC software, such as Audition or Goldwave.
1, We use IN1 as Mic input channnel. When set the PGA gain to 0dB, DC reference voltage is -48dBV(around 4mV);Then increase PGA gain,The DC reference level move down.When set the PGA gain to the max 47.5dB，the signal reference will be -24dBV(around 0.06V). In this case, customer's algorithm it is difficult to adjust with a indeterminate DC reference voltage.
2. We change the Mic input channel to IN2, change PGA Gain from 0dB to 47.5 dB, the DC reference voltage just change a little.
3.We change the Mic input channel to IN3,do the same test, change PGA Gain from 0dB to 47.5 dB, DC reference voltage is stable, the variation is very very small.
Use Input routing to change Mic input channel. (IN1/IN2/IN3)
In reply to user4013453:
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