TPS84A20 has two types of ground, PGND and AGND. According to the datasheet, PGND is the return current path for the power stage of the device and AGND is the zero volt reference for the analog control circuit. In the Layout Consideration, it is recommended to keep AGND and PGND separate from one another. Should they be connected to a single point somewhere in the PCB? I also checked the TPS84A20EVM board, there is a zero jumper to tie AGND and PGND together but it is not populated. Other than that could not find anywhere AGND and PGND tied to each other. Could you tell me if the two grounds should be tied together? Is it addressed in the datasheet?