ADC08D1520: AGND DGNS separation in ADC08D1520 or ADC07D1520

Reza

Part Number: ADC08D1520
Other Parts Discussed in Thread: ADC07D1520, ,

Hello,

I am wondering about your recommendation about separating the ADC07D1520 (AGND) from the digital part FPGA (or say PCB DGND).

By separating the AGND from DGND it will end up with LVDS DIFF pairs crossing both GND’s when they leave the ADC071520 (say AGND which is close the ADC) and then followed by DGND to get to FPGA.

Basically wondering when it comes down to achieving the best SNR of the DAQ system, would you recommend separating the ADC0xD1520 AGND from DGND or not?

Thanks,

-Reza

over 5 years ago

0 Jim Brinkhurst1 over 5 years ago

TI__Mastermind 43910 points

Hi Reza
The datasheet recommendation is to connect all ADC08D1520 ground connections to a single unified ground plane, or usually multiple ground planes in multi-layer boards. We do not recommend splitting AGND and DGND plane areas on the board. There is some discussion of this in the LAYOUT and GROUNDING section of the ADC08D1520 datasheet.
This approach is used in the ADC08D1520RB reference board design.
Best regards,
Jim B

0 Reza over 5 years ago in reply to Jim Brinkhurst1

Intellectual 765 points

Hi Jim,
Thank you for the quick response!
-Reza

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ADC08D1520: AGND DGNS separation in ADC08D1520 or ADC07D1520