The analog ground of STM32G473CBUx

[licunxu]

Hi ST expert

I'm ready to use STM32G473CBUx now. According to the datasheet, the STM32G473CBUx does not have an analog ground VSSA, only a ground VSS. I have questions:

1. The analog input of the internal ADC/DAC is referenced to the chip's VSS, or has STM32G473CBUx internally partitioned an analog ground?

2. When I design the schematic, is the analog power VDDA referenced to VSS?

[TDK · Accepted solution]

1) VSSA and VSS are bonded to the exposed pad.

2) VDDA is referenced to VSSA/VSS which is the exposed pad.

[LCE]

On most chips this extra GNDA / AGND is mostly a joke, because in the datasheet it is almost always recommended to connect these GNDs, as they are connected internally anyway.

Split GNDs can make sense (speaking more about printed circuit boards), but there's lots of things to take care of.
Even with high-end mixed-signal ICs (audio converters with fs >= 192 kHz / SNR >>= 110 dB) using one (or more) solid GND plane around / under that IC gave me the best results.

[licunxu]

Thank you for your reply