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ADS5294: when 16 bit serialization output mode, Is 2-wire mode available?

sungsik kang1
Prodigy 160 points
Part Number: ADS5294
Other Parts Discussed in Thread: ADS5295, ADS5292,

Hi. 

In datasheet of ADS5295, it says that only 1-wire operation is possible in 16bit serialization mode.

But there is no such explanation in ads5292 or ads 5294 datasheet.

Q1. Can ADS5292 and ADS5294 operate on 2-wire mode when using 16bit serialization mode ?

Q2. Is there any ADC that can operate 2-wire in 14bit serialization mode and can output frame clock at 1x sample rate?

 

I looked up a lot of datasheets on Ti homepage, but I haven't found a suitable ADC yet. I'm asking you in case I missed something.

Thanks.

  • 0
    TI__Genius 12025 points

    Hi,

    How are you?

    Thanks for choosing ADS5292, ADS5294, and ADS5295 devices.

    For your question related to ADS5295 datasheet page 75,

    you need to look at the whole line as below:

    =============

    Serialization factor 16x is:

    To be used with digital processing functions, such

    as averaging and decimation filers.

    ==============

    So hopefully you can understand, this mode is only being used for the above restriction.

    Therefore, for your question:

    question 1: when you choose to use 16bit serialization mode,

    that means you also need to turn on averaging and/or decimation filers at the same time.

    Sorry to make you confused its meaning from the datasheet.

    question 2: please provide us which ADC you are going to use.

    Because we need to ask our engineer more exact information for you.

    Thank you!

    Have a nice day!

    Best regards,

    Chen

  • 0 in reply to Chen Kung
    Prodigy 160 points

    I'm good. Thank you for your answer.

    There is confusion about question 1. 

    What i want to know is that if I can use the output in 2-wire mode when I use 16bit serilization mode.

    Q1. Does it mean that I cannot use 2-wire when I use averaging filter or decimation filter?

    And I have an additional question. If I use 16bit serial mode even if I don't have to use filters, doesn't it make 16bit by adding dummy 0 bit to the output?

    Q2. um.. The specification of ADC I want is 8CH with a sampling rate of at least 50 MSPS, which can be operated at 2-wire, and has 1x frame clock output.

          

  • 0 in reply to sungsik kang1
    TI__Genius 12025 points

    Hi,

    How are you?

    Actually the major question is related to what the total speed of the output data is.

    Because we don't know the detail information such as which device, what is exact number of bits,

    what clock speed you can run and so on. Therefore we cannot explain the final result.

    However you can consider this way:

    ADS5295 device spec has 12bit 100MSPS as max speed.

    (note: this following does not include other kind of limitations).

    (so if you try to try out of the datasheet's limitation spec, then you need to really run it on your own.)

    so its max data rate (assuming running 1-wire mode) is 12/2*100=600MHz Bit max rate

    Therefore when you want to run 16bit mode, then the max speed can be 16/2*100=800MHz is too fast.

    but when after you run decimation filter mode then you can at least lower down the total speed at least 800MHz/2 or 800MHz/4 or more.

    That is why in the datasheet, it explains when you try to use 16bit mode,

    you need to apply other mode.

    Please consider this way and hope you can understand what the limitation from the datasheet.

    Thank you!

  • 0 in reply to Chen Kung
    TI__Genius 12025 points

    Hi,

    Also for your question about:

    2-wire in 14bit serialization mode and can output frame clock at 1x sample rate

    You are mentioning of ADS5295 datasheet, right?

    1) please look at its datasheet page 75, table 20

    it shows Frame clock frequency 1/2x sample rate, TWO_WIRE=Y

    right?

    2) Therefore your question "2-wire in 14bit serialization mode and can output frame clock at 1x sample rate"

    may be from the datasheet page 77 Figure 69.

    right? 

    on the top of that page shows: 

    "Two-Wire, 12x Serialization with DDR Bit Clock and 1/2x Frame Clock"

    Therefore the picture shown below is not correct (which that case is not 1x sample rate).

    Thank you!

     

     

     

  • 0 in reply to Chen Kung
    Prodigy 160 points

    Thanks you for reply.

    I have read the datasheet of ADS5295 several times and already know that when using 14bit mode and 2-wire mode, it outputs 1/2 x frame clock.

    That's not the intention of my question, but I wanted to know if there was any ADC  product from TI which can output 1x frame clock when using 14bit output mode and 2-wire mode.!

  • 0 in reply to Chen Kung
    Prodigy 160 points

    Thanks you for reply.

    I have read the datasheet of ADS5295 several times and already know that when using 14bit mode and 2-wire mode, it outputs 1/2 x frame clock.

    That's not the intention of my question, but I wanted to know if there was any ADC  product from TI which can output 1x frame clock when using 14bit output mode and 2-wire mode.!

  • 0 in reply to sungsik kang1
    TI__Genius 12025 points

    Hi,

    How are you?

    Yes, please refer to ADS5295 datasheet on Page 75 and Table 20.

    Frame clock frequency
    1/2x sample rate, No=one-wire, Yes=two-wire

    Thank you!

  • 0 in reply to Chen Kung
    TI__Genius 12025 points

    also, please refer from ADS5295 the datasheet 

    Frame clock frequency

    1x sample rate, Yes=one-wire, No=two-wire 

    Thanks!

  • 0 in reply to Chen Kung
    Prodigy 160 points

    Thanks you. I understood it well.   

    Do TI provide sample code for capturing adc data by using xilinx's ultrascale fpga?