PCM2904: I don't succeed to acquire the second input (VinR )

Gabriele Marocco8

Part Number: PCM2904

I would like to use PCM2904 as two channels acquisition device.

I have built the circuit according to the schematics shown in figure 38 of the datasheet.

I manage to acquire correctly the input VinL (pin 12). However, I don't see any signal acquired when the input is moved to the VinR pin.. In my circuit C9 and C10 are 100nF ceramic capacitors.

I am not clear if this behaviour depends on the default configuration descriptor. Is by default the chip configured to acquire only one channel?

Thanks in advance

over 3 years ago

0 Collin Wells over 3 years ago

TI__Guru 62825 points

Hello,

The PCM2904 is a stereo ADC and it is not configured to acquire only one channel. Have you tried to verify performance using the EVM?

C9 and C10 can be ceramic capacitors without issue. When the part came out it was harder to find good performing ceramic capacitors in reasonable sizes.

0 Gabriele Marocco8 over 3 years ago in reply to Collin Wells

Prodigy 240 points

Thnaks, I finally managed to acquire indipendently the two channels. I had to change the microphone properties present in Windows control panel.

The default configuration was 1 channel

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PCM2904: I don't succeed to acquire the second input (VinR )