2 ADC's and op. amps from 1 reference (LT6655-5)

Hi! Im working on an audio acquisition system based on the LT2380-24 converter  and an Artyx 35t FPGA. I using two OPA1632 as buffers, one for each converter (the system has two channels) . 

I was planning to use the LT6655 5V reference for all the system. It worked fine with 1 channel. Do you think it will handle another ADC and op. amp or it will be better to use 2 separate references?

The overal current consumption is lower than the max. output current of the LT6655 acording to the datasheet.

  • 0
    •  Analog Employees 
    on Aug 31, 2020 10:10 PM 3 months ago

    For best performance it is recommended that one reference be used for each ADC. The REF pin is not a static node. During each conversion a series of bit tests are performed that discharge capacitors of varying size on the REF pin. Most op amps do not react well to this type of environment. If the op amp cannot settle to within 1LSB within just a few ns after each of these bit tests the ADC result will not be accurate.

  • 0
    •  Analog Employees 
    on Sep 10, 2020 7:12 AM 2 months ago

    Hi Maxim,

    Just to add to the previous reply, yes the LT6655-5V will work. But remember that there are some specs in the datasheet that is load current dependent, such as Load Regulation and Dropout voltage. 

    It is also good to know if the buffer can take the feedback response of the REF pin of the converter.

    Regards,

    Mon