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Original question:

ADS127L11: Negative voltage input without negative reference condition

ADS127L11: is able to interface to a MUX?

Di Wang
Expert 1740 points
Part Number: ADS127L11
Other Parts Discussed in Thread: ADS1256,

Hi expert,

Can I add a MUX to ADS127L11 to make it multi-channel? I think it might introduce big error to over-sampleing sigma-delta ADC during switching the channels, but I saw ADS1256.

Thanks.

  • 0
    TI__Mastermind 36280 points

    Hello Di,

    Yes, you can use a MUX with ADS127L11, but you will need to operate in One-Shot Control Mode and account for the latency times of the digital filter selected.

    Since the latency time is typically long compared to the data rate period, one of the lower latency filters such as the SINC4 operating with OSR=24 is usually preferred.  In this case the latency will be 8.13us (f-CLK=25.6MHz), and accounting for settling time of the MUX and to read the conversion result, you should be able to support an output data rate of 100ksps.

    As another example, if you want to use the wideband filter, the fastest setting is with OSR=32, and the latency time will be 170.6us (f-CLK=25.6MHz).  This will limit your output data rate when using a MUX to a maximum of about 5.8ksps.

    Regards,
    Keith Nicholas
    Precision ADC Applications