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ADS1602:

Yoshitaka Kotani
Prodigy 80 points

Part Number: ADS1602

Is the recommended center voltage of the input terminal "AINP (AINN)" 1.5V or 1.45V or 2.5V other than that?
Also, is there a recommended way to supply Vcm from the ADS 1602 to the external differential driver?

  • 0
    TI__Guru 69086 points
    Hello,

    Thank you for your post!

    The recommended common-mode input voltage is 1.5 V. Typically, the absolute voltage range on each input pin is between AVDD and AVSS; however, the ADS1602 will show the most linear performance if the input voltage on each pin remains between -0.1 V and 4.2 V. Frankly, I'm not certain why the recommended common-mode is so low. Let me confirm with a designer whether there is a specific reason for it.

    Best Regards,
  • 0 in reply to Ryan Andrews
    TI__Guru 69086 points
    After speaking with our team, I've learned that the best THD performance was measured with an input common-mode voltage around 1.45 V. This is why the datasheet is specified with that common-mode. As the common-mode increases above 1.5 V, THD seems to be degraded by about 5 dB to 7 dB.

    If you can accept a loss in THD performance, then it is ok to use a 2.5-V common-mode. Are you using the internal reference? VMID will be 2.5 V, so you could buffer this voltage and use it to set the input common-mode voltage.

    Best Regards,