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ADS1225: What is the maximum rise time permitted on the START and SCLK pins of the ADS1225?

aarmutat
Expert 3031 points
Part Number: ADS1225
Other Parts Discussed in Thread: ADS1220

What is the maximum rise time permitted on the START and SCLK pins of the ADS1225?  Want to add R-C for noise immunity.

  • 0
    TI__Guru* 98515 points
    aarmutat,


    The only timing information for communication that we give is shown in Table 5 of the datasheet. I don't think we've ever listed a max rise time for digital pins. In general, we recommend inserting series resistance of about 50Ω between the device and the microcontroller. This is usually just for protection, but might also help to slow down the pulse, when combined with the parasitic capacitance. Along with the series resistance, the digital input pins should have Schmitt triggering for better noise immunity.

    Incidentally, if you are still deciding on a data converter, I would consider the ADS1220 device. This would be considered a next generation version of the ADS1225. This would depend on what you're measuring, but both fit in a variety of applications.


    Joseph Wu
  • 0 in reply to Joseph Wu
    TI__Guru* 98515 points
    aarmutat,


    Did my response answer your question? I believe that I had clicked on "TI Thinks Resolved" but you had unclicked it. If you need more information, or I didn't answer your question, you can post a follow up.

    Hopefully, you've gotten an answer from my post. I'll leave this thread open for a couple more days, but I'll close it soon after if I don't get a response. Again, let me know if you need more information.


    Joseph Wu