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PCM1690: PSRR spec

Darren Jenkins
Genius 12531 points
Part Number: PCM1690

PCM1690 experts,

Do we have a spec to show the PSRR versus frequency for the PCM1690?

Thanks,

Darren

  • 0
    TI__Guru 53973 points
    Hi Darren,

    I do not have that curve, but the biggest influence to the PSRR will be the VCOM voltage divider. The PCM generates it's VCOM voltage (approximately VCC/2) with a simple voltage divider using 15kΩ resistors. This means that without filtering on the VCOM pin, your PSRR could really be -6dB! For that reason we recommend a capacitor on the VCOM pin to filter out the supply noise from the output. You can assume the impedance of the two resistors in parallel, so fC = 1/(2π×7.5kΩ×Ccom).

    Thanks,
    Paul