• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 46 subscribers
  • Views 498 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ADC12D1800RFRB: Over-range for both channels when switching to external clock

Edgar Antillon
Prodigy 70 points

Part Number: ADC12D1800RFRB

Hello,

We are using the ADC12D1800RFRB. When switching to an external clock  the over-range LED turns on for both channels without the clock having been turned on. Even when the clock is turned on, the LED still appear to be turned on. We are trying to figure out as why this happens but we have yet to figure it out. We have the input signal on the I-channel set  where the ADC is shown to work properly when looked at in wavevision. 

  • 0
    TI__Mastermind 43930 points

    Hi Edgar

    Early revisions of the ADC12D1800RFRB have an on-board relay to enable dynamic switching between on-board and external clock sources. The current version shipping requires minor component re-work (moving 0 ohm resistor R180 in the clock path from the B location to the A location) to enable external clocking. Can you inspect the ADC12D1800RFRB that you have to determine which version it is and confirm whether you have re-located the resistor if needed?

    If the resistor has been reworked, it is also necessary to select External Clock in the Wavevision5 GUI Registers tab Clock Selection pull-down. This disables the on-board PLL to prevent cross-talk from that clock source.

    Thanks,

    Best regards,

    Jim B