I am using a four-layer PCB with the following stack up: top signal, ground, 3.3V VCC, and bottom signal.
All of my components require a 3.3V input except for this sensitive optical sensor (MAX30102) that needs both 1.8V and 3.3V inputs. In the MAX30102 datasheet, the 1.8V needs to run to a separate ground from the rest of the system.
How should I go about separating the ground planes? I am using two linear voltage regulators in parallel and have attached an image of my design.
Pad 12 is the ground for the 1.8V input and pad 4 is the ground for the 3.3V input on the MAX30102. How should I connect pad 12 to ground to minimize noise? Furthermore, how do I tie both 1.8V and 3.3V grounds together?
I'm guessing that I make a separate ground plane underneath anything that connects to 1.8V and then connect that to the ground of the 1.8V linear voltage regulator.
Or maybe, I have to connect the 1.8V ground to the main ground source at only a single point with a track? Currently, the second layer ground is tied to all of the other components powered by 3.3V.
Please let me know, I'm a student.