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ADS1263EVM-PDK: seek the appropriate design for Analog industrial interface

user6494725
Prodigy 30 points
Part Number: ADS1263EVM-PDK
Other Parts Discussed in Thread: ADS1263, ADS8684, OPA2188, ADS8638, OPA2182, OPA187, ADS8694, ADS8684A

Hello;

        I am design a circuit for 0/4~20mA &±10V、±5V、0~1.25V、0~2.5V、0~5V、0~10V converters to digital signal。Althought TI Official website suggest base ADS1263 design,but ADS1263 max sopport ±5V and not support 4~20mA(when input 4mA,get the voltage isn‘t 0V),so I can hope you can suggest a better&appropriate design for my demand。By the way,I self select several design:ADC:ads8638、ads8684(a);OPA:opa187、opa2182、opa2188,so can you give your advice?include reference design circuit best~

  • 0
    TI__Mastermind 35520 points

    Hi user6494725,

    Apologized for late response. For 4~20mA, here is a reference design using ADS1263, please check:  4- to 20-mA Analog Input Module Reference Design for Safety Applications

    For voltage input, there are different solutions to design a signal conditioning circuit for using ADS1263, a simple solution is using a precision resistor divider for high voltage input(e.g. +/-10V or +/-20V) on the ADS1263's input.

    Can you provide more information about your design?

    1. How many channels do you need for V and I input? Do you need to change the range on each channel?

    2. What's the highest sampling rate required or settling time requirement per channel?

    3. Any input impedance requirement?

    4. Is input floating(disconnection) detection required?

    Thanks&Regards,

    Dale

  • 0
    Prodigy 30 points

    Hi Dale，

    Thanks Dale.I think the solution for using precision resistor divider for high voltage input(e.g. +/-10V or +/-20V) on the ADS1263's input is not a best solution.I think

    the best solution is using the opa and the ads1263 cannot configure according to different input.

    1. How many channels do you need for V and I input? Do you need to change the range on each channel?

    Answer:4channels.wo probably need chang the input voltage range

    1. What's the highest sampling rate required or settling time requirement per channel?

    Answer:110kps Can satisfy

    1. Any input impedance requirement?

    Answer:more than 1MΩ

    1. Is input floating(disconnection) detection required?

    Answer: If there's something better, it doesn't matter

  • 0 in reply to user6494725
    TI__Mastermind 35520 points

    Hi user6494725,

    110ksps data rate is critical for Delta-Sigma ADCs including ADS1263. If your voltage inputs are single-end signals(I believe so). ADS8484A(16-bit) or ADS8694(18-bit) will be a simple and precision solution which can meet all your requirements. Please let me know if you have any question about this solution.

    Thanks&regards,

    Dale

  • 0 in reply to Dale Li
    Prodigy 30 points

    Hi Dale，

               the last question:

    what about using the OPAopa187/opa2182/opa2188  drive ADC ADS8638/8664/8694,Is it appropriate？if not ，please Recommend，THS

  • 0 in reply to user6494725
    TI__Mastermind 35520 points

    Hi user6494725,

    Usually ADS8684A and ADS8694 do not need an amplifier to drive because it has an integrated PGA on each channel and the input impedance is 1Mohm. For different input signal, a proper range can be selected or changed per channel. ADS8638 is a conventional switch-capacitor input SAR ADC, it requires an amplifier to drive regarding your sampling rate requirement. Please check these ADCs' datasheet also TI Precision Labs videos and materials.

    Regards,

    Dale