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ADS114S06B: Schematic Review

Part Number: ADS114S06B

We are using mentioned device in one of our projects. It is interfaced with SC20. I request for the schematic review. Schematic is attached.

Control_Board.pdf

  • Hi Varun,

    There are several things that are unclear.  Primarily it relates to the supply derivation.

    • Where does VCC7V, VCC5V and VCC5V_Precision supplies come from?  Only net labels are shown.
    • How is the DVDD supply to be applied?  There is a voltage divider (R224 and R25) that are DNP and R223 connected in series with VCC3V3_M.2 but it is unclear where this supply originates.  The DVDD supply must have a low impedance source.  DVDD is the main core voltage used by the ADS114S06B and even though the average current may be low, there will be periodic current demands that must allow required current to be available when necessary.
    • C23 (connected to AVDD) must be at least 330nF as per datasheet in section 11.4.
    • It is not clear what the output of the sensors will be and how the input voltage relates to the ADC input.  In general you should have antialiasing/noise filters on the ADC inputs.

    Best regards,

    Bob B

  • Hi Bob,

    Thanks for the quick response. Please see the attached file which has includes the power supply section.

    • VCC3V3_M.2 rail is having enough capacity to power the DVDD core supply. But there are chances that VCC3V3_M.2 may become DNP in future, that is why the resistor divider option is provided as a backup.
    • Will change C23 as per your recommendation to 330nF cap.
    • Sensor outputs A1 thru A4 are well filtered as they come from the pre-calibrated sensor board. Will think of adding noise filter to A0.

    Thanks,

    Varun
    ControlBoard_Power.pdf

  • Hi Varun,

    I highly recommend not using a voltage divider for DVDD.  This is the core digital supply (what makes the digital work) and the current demand is not static but rather dynamic.  Also, your resistor divider values will provide a supply lower than the required DVDD voltage.

    Best regards,

    Bob B