AD4030 v. reference ground

Hi, RalphLoader .

Can you try checking this thread if it will help you? (+) AD7874 VDD(3pin, 9pin) Conection - Q&A - Precision ADCs - EngineerZone (analog.com)

Regards,
Jo

I don't think it does. That talks about connecting AGND and DGND.

The situation here is a bit different. The AD4030 appears capable of sub-µV precision (with appropriate oversampling).

The potential difference between the AGND at the reference and at the ADC may well be hundreds of µV, and vary both with temperature and ground plane current, destroying the accuracy of the device.

Other precision ADCs (e.g., the AD7177) avoid this by having a dedicated reference ground pin, giving you differential routing between the reference and the ADC, and isolating that from all the other ground currents.

The question is how to recover the accuracy of the ADC in the absence of a dedicated reference ground.

Hi, RalphLoader .

To answer your question, even though the AD4030 do not have a reference ground, we can guarantee that this would not have a trade off to its performance. The AD4030 has an internal capacitor and a buffer to its REFIN pin to help make the reference stable whenever changes from its reference happens. This can guarantee a stable reference to the device. On the other hand, for its PCB, you can use a solid ground plane under the AD4030-24/AD4032-24 and connect all the analog ground (GND) pins and digital ground (IOGND) pins to the shared ground plane to avoid formation of ground loops.

Warm regards,
Jo