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ADC32RF45: Turning off One Channel

James Chen26
Prodigy 65 points
Part Number: ADC32RF45
Other Parts Discussed in Thread: ADC32RF80, ADC31RF80

Hi, 

I'd like to turn off one of two channels of the ADC and observe the power consumption change, just to verify the numbers provided from Table 117 of the datasheet:

However, I haven't been able to turn of either Channel A or B. I've tried checking the box for "ChB PDN" and observed the register bit change in the Low Level View, but the current draw remains the same.

Global PDN works and I was able to turn off the ADC altogether, but I'd like to turn off just one channel at this time.

Is there another register/setting that I'm supposed to modify? Any help is appreciated!

Thanks,

James

  • 0
    TI__Mastermind 29220 points

    Hi,

    I support the ADC32RF45 itself, but I do not support that EVM with ADC and DAC both on it that you are using, or the SPI GUI that was made for that EVM.  I am assigning this posting to the person who developed that EVM and the SPI GUI for it.  The ADC portion of that SPI GUI was copied from an earlier one that I had developed for the ADC EVM.

    But maybe we can solve the issue in the meantime anyway.   In the latest datasheet for the ADC32RF45 on the TI web they removed the SPI register bits for powering down channel A.   In one of my early GUIs I had the controls in the GUI for powering down either channel A or B because that was in an early datasheet draft.  My current GUI has removed the control for powering down channel A because that is no longer in the datasheet.    I still have the control for powering down channel B.  But also in the released datasheet is now a new field in the SPI for Powerdown ChannelB Enable.  PDN CHB EN.  That is in address 0x39 of the master page.  I added that enable bit to my ADC32RF45 SPI GUI, but that was after the GUI for the TSW40RF80 was made.    Check the datasheet for the ADC32RF45, and then in the SPI GUI low level tab set that bit for the channel B powerdown enable, and then set the channel B powerdown.  I am hopeful that that is what will be needed to power down channel B. 

    Regards,

    Richard P.

  • 0 in reply to Richard Prentice
    Prodigy 65 points
    Great! I followed your instructions and was able to turn off channel B.

    However, I lost the JESD link to HSDC Pro...
    I was using the default ADC32RF80_LMF_8821 during two channel operations (at the default 2949.12 MHz sampling rate), and I switched to ADC32RF80_LMF_4421 but neither of the configuration work.

    How do I make sure the JESD link stays synchronized?

    Thanks,
    James
  • 0 in reply to James Chen26
    TI__Mastermind 29220 points

    Hi,

    I'm glad we figured out how to turn off channel B.    But then yes, that will cause issues for the HSDCPro and TSW14J56.   The ini file for the LMFS_8821 mode will be looking for the initial lane assignment sequence on all 8 lanes and we now have turned off four of the lanes.   So HSDCPro will time out.   What will be needed will be an ini file for the HSDCPro that tells the FPGA that there are half as many lanes active.    You were on the right track looking at the device selection for LMFS_4421 as that *will* be the LMFS for one channel in Dual Band Complex output mode.    But none of the LMFS_4421 files that come with the HSDCPro are the right ones.    If you look at the two other LMFS_4421 modes listed in the data sheet in table 17, neither of them use the correct four lanes.   One of them uses lanes DA0, DA1, DB0, DB1.  Another uses lanes DA1, DA2, DB1, DB2.   What you will need is an ini file for a mode that uses lanes DA0, DA1, DA2, DA3.    I have made such a file and attached it here, but I have not checked it on the bench yet.  (I don't like to put out files that I haven't checked because it is so easy to enter a typo.  But I will go check it later today and take a chance right now in the interest of time.)  I named it ADC31RF80_LMF_4421 to differentiate it from the other files with that LMFS, naming it as if we had a part number for a one channel version of the ADC32RF80.   You would want to copy this file in where the HSDCPro installed, namely Program Files(x86) > Texas Instruments > High Speed Data Converter Pro > 14J56revD Details > ADC Files.  And re-launch HSDCPro.

    Regards,

    Richard P.

    ADC31RF80_LMF_4421.ini