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ADS4222EVM: how to test ADS4222EVM without TSW1400 ?

user5086416
Prodigy 50 points
Part Number: ADS4222EVM
Other Parts Discussed in Thread: SN74AVC16T245, ADS4222, FMC-ADC-ADAPTER

As titled, I want to test ADS4222EVM without TSW1400.

I've check the jumper settings and all of them are in the correct (default) positions.

But I'm not sure with the input clock spec, such as waveform, frequency, offset, ...,etc.

The highest frequency I can get from my signal generator is 25MHz.

If this frequency is acceptable, how much is the consumed current ?

The user guide says that clock amplitude should be 0.6Vrms (approximately 0.8Vpp), but did not mention about waveform and offset.

Should I use square wave or sine wave signal ? And how much offset is appropriate ?

I want to use test patterns to verify the LVDS output, and I used the ADS42xx_58C28 GUI to program the serial interface register map.

I enabled the digital function and set the test patterns of both channel to be alternating (or digital ramp).

Are there any other necessary setting items ?

Last question, can I measure LVDS output directly on the connectors J1 and J2 ?

I tried to do so but didn't see any waveform on oscilliscope.

Thanks a lot for helping me out.

  • 0
    TI__Mastermind 20541 points
    Hi,

    We are looking at your question will get back to you soon.

    Regards,
    Neeraj
  • 0 in reply to Neeraj Gill
    TI__Guru* 91947 points

    User,

    Setup the board for serial SPI interface. Open the EVM GUI and do a send all to reset the board. Provide a 25MHz clock with at least -5dBm of power. This should be a sinewave centered about 0V.

    You should see the output pins toggle after this. If you are using the board in parallel SPI mode, toggle the reset button after power up. I have the board running in our lab with 25MHz clock @ 0dBm, and the current draw on the 5V input source is only 0.081 Amps.

    To enable the test pattern, set address 0x42 to 0x08 to enable the digital functions. Set address 0x25 to 0x04 to turn on the ramp for CHA and set address 0x2B to 0x4 for CHB.

    Regards,

    Jim

  • 0 in reply to jim s
    Prodigy 50 points
    Hi, thanks a lot for your reply.
    I don't understand about "25MHz clock with least -5dBm of power."
    I cannot find any attenuation option on my signal generator.

    I provided a sine wave with 700mVpp and zero offset for input clock.
    And used ADS42xx EVM GUI to enable the digital function and set the test patterns to be toggle.
    The consumed current is about 0.114 Amps.
    But I stil get nothing on the connector J1.

    There's another question,
    I've seen the circuit schematic and layout PDF file of this EVM board.
    In schematic file, there is a SN74AVC16T245 bus transceiver connected between the LVDS output pins and the connector J1.
    But in the layout file I cannot find this component.
    This difference confused me, can I measure the LVDS output directly on the connector J1 ?

    Thanks a lot for helping me out.
    Regards,

    User
  • 0 in reply to Neeraj Gill
    Prodigy 50 points
    Hi,
    Thanks a lot for your support.
  • 0 in reply to jim s
    Prodigy 50 points
    Hi, Sorry I didn't see that SN74AVC16T245 is denoted DNI in schematic file.
    And I also found it in layout file.
    It seems that SN74AVC16T245 is required when CMOS output mode is chosen.
    And so are the connectors J1 and J2.
    If I didn't change output mode (DDRLVDS) I could only measure these LVDS signals through the connector J8.
    Does the above statement correct ?

    Thanks a lot for helping me out.
    Regards.
  • 0 in reply to user5086416
    TI__Guru* 91947 points

    User,

    That is correct. By default, the board is setup for LVDS output mode. You would need to remove some r-packs and install the SN74AVC16T245 before you can use the board in CMOS output mode. Is you board sending LVDS data out now? Are you still having issues?

    Regards,

    Jim

  • 0 in reply to jim s
    Prodigy 50 points
    Hi Jim,
    First of all, I really appreciate for your support.
    Yes, I didn't change default setting, therefore I think the output mode of ADS4222 is in LVDS mode.
    But I don't have TSW1400EVM to receive data.
    Could you give some advices on how can I measure signals directly from the connector J8 ?
    Or if I want to use my own FPGA board to receive LVDS data, how can I connect these boards with each other through the connector J8 ?
    Thanks a lot for helping me out.

    Best regards,
    User
  • 0 in reply to user5086416
    TI__Guru* 91947 points

    User,

    Depending on what type of connector you have on your FPGA board, TI sells two adapters that may work for you. One is the HSMC-ADC-Adapter board and the other is the FMC-ADC-Adapter card. I have attached the schematic of both of these boards for you to verify with your FPGA board. Another option is to purchase the TSW1405EVM, which is a low cost capture card.

    Regards,

    Jim

    7840.SCH_HSMC_ADC_BRIDGE_REV_C.pdf3386.FMC-DAC-ADAPTER_D_SCH.pdf