ADC12DJ3200: SYSREF signal question

Ryker She

Part Number: ADC12DJ3200

Tool/software:

Hi expert,

My customer is evaluating ADC12DJ3200, they want to know if the SYSREF can be set to 0V or let them float after the JESD204B connection is successfully established? Appreciate your reply.

Best Regards,

Ryker

7 months ago

+1 Eric Kleckner 7 months ago

TI__Expert 6180 points

Hi Ryker,

They can let the sysref float the common mode after aligning. But before they switch the sysref signal off they should disable sysref processing and sysref receiver subsystems.

Thanks,

Eric

0 Ryker She 7 months ago in reply to Eric Kleckner

TI__Expert 4680 points

Hi Eric,

Customer found that the transmission was out of sync when the JESD204B connection is successfully established and disable the receiver. Is it normal? Thanks.

Best Regards,

Ryker

0 Ryker She 7 months ago in reply to Ryker She

TI__Expert 4680 points

Hi Eric,

The transmission was out of sync when R&D add below code (as the arrow points) and the transmission can be synchronized when they delete below code. Please help to confirm if it is normal. Thanks.

Best Regards,

Ryker

0 Ryker She 7 months ago in reply to Ryker She

TI__Expert 4680 points

Hi Eric,

Please help to confirm this issue ASAP.

BR,

Ryker

0 Eric Kleckner 7 months ago in reply to Ryker She

TI__Expert 6180 points

Hello Ryker,

Why would they only turn off the sysref receiver and not also sysref processing. To correctly stop the part from processing sysref both must be turned off.

Thanks,

Eric

0 Ryker She 7 months ago in reply to Eric Kleckner

TI__Expert 4680 points

Hi Eric,

R&D said they have tried below code (0x40 → 0x00) to turn off sysref receiver and sysref processing, but the transmission was still out of sync. Could you provide the sample code which can turn off sysref receiver + sysref processing and keep the 204b transmission synchronized?

BR,

Ryker

0 Ryker She 7 months ago in reply to Ryker She

TI__Expert 4680 points

Hi Eric,

Please help to analyze this issue. Thanks.

BR,

Ryker

0 Eric Kleckner 7 months ago in reply to Ryker She

TI__Expert 6180 points

Hello Ryker,

I dont have any example code but all they need to do is follow the process laid out in the datasheet. So to turn on the ysyref subsytem you enable the SYSREF_RECV then SYSREF_PROC then to disable all you do is the reverse. Also please not that they should disable the sysref subsystem on the ADC before turning off the SYSREF source as any glitches in the sysref source would casue a realignment.

Thanks,

Eric

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ADC12DJ3200: SYSREF signal question