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PCM1808: channel interference signal

CS kk
Intellectual 400 points
Part Number: PCM1808

When the input analog signal of VINR pin is more than 3Vpp, the VINL will be disturbed;

When the input analog signal of VINL pin is more than 3Vpp, the VINR also will be disturbed;

  • 0
    TI__Guru 63885 points

    Hello,

    3Vpp is the maximum full-scale input level for the PCM1808 before it will saturate and clip and if the signals are larger than this then it's possible for abnormal output behavior to occur.  However, before we come to any conclusions could you please share a more complete schematic showing where the two input signals come from and the passive input network attached to them? VINL has a 22uF capacitor to AC couple the input but it's not clear how the connections to VINR are being made. 

    Can you also probe the analog input signals going to the PCM1808 both before and after the AC coupling capacitors?  The notes on the schematic say 2.5Vrms which is actually 7.07Vpp, not 3Vpp as suggested in the message. A 7.07Vpp input signal is definitely too large and will likely violate the absolute maximum input voltage levels of the product.