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ADS8568: Can ADS8568 accept unipolar analog input signal？

Ray Ni
Prodigy 60 points
Part Number: ADS8568

The voltage range of MicPhone signal is usually between 0~3.3V. Can ADS8568 accept this unipolar analog input signal？So, can HVDD connect to 3.3V and HVSS connect to Ground?

  • 0
    TI__Guru 64086 points

    Hello Ray,

    Thank you for your post and welcome to our forum!

    The ADS8568 requires two pairs of analog supply voltages: AVDD / AVSS and HVDD / HVSS. The HVDD / HVSS supplies are intended to allow the analog inputs to accept single-ended, bipolar signals. If your input signal only ranges from 0 - 3.3 V, you may use HVDD = 3.3 V and HVSS = GND. Please refer to the Recommended Operating Conditions table for recommended supply configurations.

    Regards,

  • 0 in reply to Ryan Andrews
    Prodigy 60 points

    Hello Ryan,

    Thanks for your reply!

    According to the Recommended Operating Conditions table: 5V < HVDD < 16.5V ,  -16.5V < HVSS< -5V. However, the Absolute Maximum Ratings table shows :  -0.3V < HVDD < 18V ,  -18V < HVSS < -0.3V.

    If, I still use HVDD = 3.3 V and HVSS = GND. What problems may be caused in this case?

    Alternatively， can I use HVDD =5V and HVSS = -5V ？It covers the range of 0 - 3.3V

  • 0 in reply to Ray Ni
    TI__Guru 64086 points

    Hello Ray,

    Reducing the HVDD/HVSS supply to only 3.3 V and 0 V may lead to degraded performance. Please follow the guidelines in table 7.3.

    +/- 5 V for the HVDD/HVSS supplies is ok.

    Regards,