I am designing an instrument based on the DDC112 as a student project.
The lower part of figure 29 in the datasheet shows the DVDD power supply derived from the AVDD supply with a < 10 ohm isolation resistor. I would be grateful if someone could explain how the resistor protects the analog supply from noise. The isolation resistor is absent in Application Note MULTI-DDC112 BOARD DESIGN (figure 1a) as well as in User Guide DEM-DDC112U-C EVALUATION FIXTURE (figure 10).
I also noticed that the Application Note MULTI... (figure 1a) has decoupling capacitors of 1uF at the supply inputs and the User Guide DEM-DDC.. (figure 10) has 10uF + 0.1uF. Why so?