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ADS5409: CLOCK AND TRIGGER PIN

Vishnu
Prodigy 120 points
Part Number: ADS5409
Other Parts Discussed in Thread: ADS5402EVM, , ADC12DL3200, LMK04832, LMK04828, LMK61E08

Tool/software:

Hi Team,

1) In the below image of ADS5402EVM, Pin number P10, N10 are used as trigger pin function. But in datasheet it mentioned as do not connect pin. What should we consider this pin function in our design?

2) How to give Clock input for ADS5409

We referred some other ADC part number - ADC12DL3200, clock signal from LMK04832 is given to both FPGA and ADC. 

Do we also need to implement the same for ADS5409 and FPGA.

3) Since ADC5409 sampling rate is 900Msps. We selected this clock oscillator which supports LVDS 900MHz. Shall we proceed with this part number or suggest any other part number supports for ADS5409.

  • 0
    TI__Mastermind 41330 points

    Hi Vishnu,

    1) Per the datasheet, this is not a supported feature on the ADS5409. The reason this circuit is there on the EVM, is that the EVM covers several devices from this family and some may have that feature supported.

    2) The LMK04832 will work for this application to clock both the ADC and FPGA. You can also consider the LMK04828 as well. Either should do the job.

    3) I would suggest a cleaning, better phase noise oscillator with a PECL or sinewave outputs will provide a cleaner/sharper edge. Something like this will do: www.crystek.com/.../vcxodetail.aspx

    Regards,

    Rob

  • 0 in reply to Rob Reeder
    Intellectual 370 points

    Hi Rob,

    Thank you so much for your response.

    Please kindly let me know the below queries.

    We are using the ADS5409 ADC in our design and have the following queries regarding its clock implementation:

     1. In some reference designs of ADC12DL3200, clock signal from LMK04832 is given to both FPGA and ADC. i.e., the clock generator output is connected to both the ADC and the FPGA, as shown in the attached image. Should we follow a similar approach for our design, or is it sufficient to directly connect the clock oscillator output to the ADC input?

     2. We have selected the LMK61E08 as a programmable oscillator which supports a 900 MHz to design clock section of ADS5409. Could you please confirm if this component is adequate for the ADS5409 requirements? If not, kindly suggest an alternative part number that meets the specifications.

    Thanks,

    Bhuvaneshwari

  • 0 in reply to Bhuvaneshwari K
    TI__Mastermind 41330 points

    Hi Bhuvaneshwari,

    1) If you want the clocking to come from the same source, then its best to use the LMK04832 or 04828.

    2) I suggested a very clean oscillator above, the LMK610E08 might not be clean, low in phase noise, enough for the ADS5409.

    Regards,

    Rob