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ADS1672: 5V AVDD shared with external oscillator

Kazuto Tatsumi
Intellectual 2820 points
Part Number: ADS1672

Hi team,

My customer is considering the power supply structure shown in below, however there is a concern to use the same 5V supply with external oscillator for ADS1672. Do you have any advice to avoid noise issue, otherwise does the customer need to separate the power supply?

6V -> LM2940CT-5.0 -> ADS1672
                                  -> 20MHz External oscillator (for ADS1672)

Regards,
Kazuto

  • 0
    TI__Mastermind 46130 points

    Hello Kazuto-san,

    The external oscillator can be powered from the same 5V supply as the ADS1672.  The ADS1672EVM uses the same supply and is able to get datasheet performance.

    Including power supply bypass capacitors and good board layout is needed for best performance.  The oscillator should only directly drive the CLK input of the ADS1672.  If the oscillator needs to be fanned out to other devices, such as the host MCU, then some type of clock buffer should be used that is powered from a separate digital supply.

    Regards,
    Keith Nicholas
    Precision ADC Applications