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Help needed in interfacing and testing ADS54RF63EVM

Basil Mohammed
Prodigy 240 points
Other Parts Discussed in Thread: ADS54RF63, FMC-ADC-ADAPTER

Hi,

My lab has bought a ADS54RF63EVM board, which I would like to use for a project. To begin with, I have to familiarize interfacing with the ADC board.

I am totally new to working with these boards. So, it would be really great if any inputs could be given for the following :

1. What is the best way for me to test the board?
2. How do I take the digital output from the board? 
 -- I understand that a touchless probe breakout board has been provided. Is there any other option to take the data out? 
 -- I also have a Xilinx Virtex 6 FPGA board and DAC34SH84EVM board. Will they be of any help in getting the output?

This is quite urgent for any progress in my work. Thanks a lot in advance.

Basil.

badaboss@gmail.com

  • 0
    TI__Mastermind 29220 points

    Hi,

    you will need to have a high quality signal source for generating a sample clock to supply to the ADS54RF63 EVM and a high quality signal source to generate an input signal to the analog input of the EVM.   I stress the need for a high quality signal source because phase noise (or jitter) on the signal sources will limit the signal to noise ratio that you can observe from your ADS54RF63 EVM.

    You will need to have a way of capturing the sample data from the EVM so that you can evaluate the data or do some kind of processing of the data to fit your needs.  The easiest way to capture the digital sample data is with one of our FPGA-based capture cards such as the low cost TSW1405 or the more fully featured TSW1400.  Take a look at the web pages for these two capture cards and take a look at the User's Guide for the High Speed Data Converter Pro software that is used with these two capture cards to see what they can do.

    Since you have a Xilinx development platform you could also use the FMC-ADC-ADAPTER http://www.ti.com/tool/fmc-adc-adapter to connect the EVM straight to your development platform, but then you would have to create your own Xilinx firmware to capture the data from the ADC and so something with it.  We don't provide firmware for your development platform.

    The breakout board that you mentioned is for connecting the sample outputs of the EVM up to a logic analyzer to capture the sample data.  The breakout board has landings for a Tektronix or an Agilent logic analyzer pod to connect to the signals, but you would have to have the logic analyzer, the logic analyzer pod, and the logic pod mounting shell that solders to the breakout board for your particular pod.  We don't pre-install the logic pod shell on the breakout board because we don't know what logic analyzer you might be using. 

    For signal sources there is also one more option:  TI has a low-cost system evaluation kit (HSDC SEK-10) that can provide a clean (filtered) 10MHz signal for the analog input http://www.ti.com/tool/tsw2110evm and a clean sample clock for the clock input http://www.ti.com/tool/tsw4806evm.  The low cost tools may be purchased as a kit or as indivudual pieces.  The User Guide and video at the links above give more information about these low cost tools.

    Regards,

    Richard P.

  • 0 in reply to Richard Prentice
    Prodigy 240 points

    Hi Richard,

     Thanks a lot for your very detailed reply. I am currently testing the ADC EVM board by giving analog input via a 500 ohm potentiometer. I am varying the input value and trying to observe the output on the breakout board. To take the output, I am using multimeter probes on the pins of the breakout board. 

    The datasheet has mentioned the corresponding pins for the breakout board. But, I have the following issues :

    1. Is it okay to test the outputs via multimeter ?
    2. What does the D0_P and D0_M mean ?
    3. I am observing all the D0_P, D0_M, D1_P, D1_M , etc. upto D11_P and D11_M as high itself. Is it right?

    Thanks a lot for the help.

    Basil Mohammed
    badaboss@gmail.com

  • 0 in reply to Basil Mohammed
    TI__Mastermind 29220 points

    Hi,

    The digital sample outputs are use LVDS signalling, so search for LVDS and read up on that.  LVDS is a differential signalling, so every 'signal' is really a pair signal pins that are complement of each other.  While one pin is 'high' the other pin is 'low'.

    if you use a multimeter to look at the voltage level of the pins, then for pins that are not switching you would see one pin of the differential output high and the matching pin low.  But for output pins that are switching the multimeter will simply show you the average of the high and low voltage levels over time. 

    Also, the analog input signal needs to be differential and the voltage levels need to correspond to the data sheet requirements.  So if you wish to enter a constant input voltage, then that voltage needs to be converted to differential and each side of the differential signal needs to have its voltage swing centered around the datasheet requirement for the common mode voltage (called VCM or CM).  The EVM you bought has a transformer coupled input circuit and the trnasformer does the conversion from a single ended input signal to differential and the transformer also provides the AC coupling so that the level of the differential signal could be biased to the desired voltage levels.  But transformers do this for AC signals - not for static DC signals.  The transformer coupling on the EVM will only work for input frequencies above the low frequency cutoff specified for the transformer used - usually about 1MHz or more.  I don't know where you are injecting your voltage from your 500 ohm potentiometer - but this voltage needs to conform to datasheet requiremnts: differential and biased to be centered about 2.5V common mode.

    Regards,

    Richard P.

  • 0 in reply to Richard Prentice
    Prodigy 240 points

    Hi Richard,

     Thanks a lot for the help. I gave a 10 MHz sinusoidal wave as single ended input to the EVM board, and observed the outputs from the breakout board, with the help of a DSO (Digital Storage Oscilloscope). 

    Regards,
    Basil M.