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PCM1808: Analog Input Voltage Query

Ernest Yong
Expert 5070 points

Part Number: PCM1808

Hi Team,

I have a question regarding the Analog Input Voltage. When our DUT (Device Under Test) is in idle mode, an input signal activity on VinL and VinR can be generated. During this activity, the signal can go as low as -628.59mV.

Does TI PCM1808 chip okay to have this -628.59mV signal on VinL or VinR input pin?

 

See below for the plots.

 

Note: All signals below are measured on the pin of the Chip.

Thank you for your time!

  • 0
    Prodigy 140 points

    According to the Absolute Maximum Ratings (section 6.1) in the datasheet, the minimum input allowed on VinL and VinR is -300mV to ensure normal operation of the device.  Somewhere around -650mV current will be injected on the pin into the substrate, as which will cause operational disturbance. As long as it is limited to <= 10mA then no damage should occur.

    A small series resistor would be sufficient.  Typical values for a passive anti-alias filter on the input pins (Figure 26) of 100-220 ohms should protect against small excursions.

    In my experience, the operational disturbance includes pops, clicks, and possibly bursts of static on the digital output of both channels - even if the adjacent channel is within its normal input voltage range.  Normal operation resumes once the current injection ceases, it is not necessary to reset the device.  Hope this answers your question!