• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 46 subscribers
  • Views 534 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ADS127L01 aliasing behavior

Friedrich Kaufmann
Prodigy 90 points
Other Parts Discussed in Thread: ADS127L01

Hi,

I would like to use the ADS127L01 sigma-delta ADC. This is a high order chopper stabilized sigma-delta modulator plus all necessary digital filters. A further device, which is interesting for me is the AD7768 from Analog Devices. There I found a diagram concerning the aliasing, if I input a high frequency signal (figure 91 of that datasheet). Du to the chopper method there is some sensitivity in the frequency range from halve the data rate up to the frequency of the modulator.

Is there any similar diagram available for the ADS127L01?

This sensitivity of the ADC is important for the design the anti aliasing filter in the ADC driver.

Best regards,

Kaufmann Friedrich

  • 0
    TI__Guru 66186 points
    Hello Kaufmann,

    Thanks for your question. To understand the aliasing sensitivity in the ADS127L01, you simply need to look at the frequency response of the digital filters (pages 29-30 for the Low-Latency filters and pages 32-33 for the Wideband filters).

    The ADS127L01 uses a fixed chopping rate, but does not exhibit the same artifacts shown in Figure 91 of the AD7768 datasheet. Instead, our wideband filters provide a more consistent stopband attenuation level, about -116dB or better, from the end of the transition band (either 0.5*fDATA or 0.55*fDATA) until 1xfMOD.

    Please let me know if you have any further questions.

    Best Regards,