ADS131A04EVM: Request for PCB layout file to review how AVSS and GND plane connectivity

Mahesh Hooli

Part Number: ADS131A04EVM

Hello Team,

We are using ADS131A04IPBSR ADC in our design, and its been operated in single supply (+5V) mode. We have connected AVSS (pin 10) to Analog ground plane and GND (pin 27) to Digital Ground plance. Both are tied together at common point using 0 OHM resistor.

Could you please suggest if this approach is good for ADC performance ?

Can we get PCB layout file of ADS131A04EVM to verify the ground connectivity ?

The placement and layout is shown in the picture below,

over 6 years ago

0 Ryan Andrews over 6 years ago

TI__Guru 62756 points

Hello Mahesh,

Attached is a ZIP file with the ADS131A04EVM gerber files. The schematic is already included at the end of the User Guide.

ADS131A04EVM_gerbers_(PA015A).zip

Let me review your layout and get back to you shortly. Do you also have a schematic that you can share?

Best Regards,

0 Mahesh Hooli over 6 years ago in reply to Ryan Andrews

Intellectual 740 points

Hello Ryan,

Thanks for sharing the gerbers. Please find the attached schematics for review. It has ADC and Power circuitry .

Please let me know if you have any questions.

Thanks

Mahesh

ADC_Schematice_V0.7.pdf.zip

0 Ryan Andrews over 6 years ago in reply to Mahesh Hooli

TI__Guru 62756 points

Hello Mahesh,

I did not find any obvious mistakes in the schematic, looks ok to me!

Regarding the 0-ohm resistors between AGND and DGND, I think having multiple places to short them together is a good idea. At least one should be placed as close to the device as possible. The stitching vias should also help keep the two ground planes very close together as well.

Best Regards,

0 Mahesh Hooli over 6 years ago in reply to Ryan Andrews

Intellectual 740 points

Hi Ryan,

Thank you very much for your review comments. Sure we will keep one 0Ohm resistor close to the device

After going through the EVM gerbers, we connected Digital ground (DGND) to both 5V and 3.3V power supplies.

Kept VREF IC connection to analog GND. Now the Ground plane split looks as shown below.

Only change to the schematics is the ground plane reference for 5V analog power supply. Please find the updated schematics attached.

ADC_Schematics_Feb6.zip

0 Ryan Andrews over 6 years ago in reply to Mahesh Hooli

TI__Guru 62756 points

Hi Mahesh,

Nicely done! That way, all the analog return currents will flow through the digital side of the board back to the power source instead of the other way around. Let us know if you have additional questions!

Best Regards,

0 Mahesh Hooli over 6 years ago in reply to Ryan Andrews

Intellectual 740 points

Thank you Ryan for reviewing and sharing your thoughts !

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ADS131A04EVM: Request for PCB layout file to review how AVSS and GND plane connectivity