I would like to chain in series multiples LMZ31704 (1V, 1.8V and 3.3V).
First 1V Buck is powered ON, then buck 1.8V, then 3.3V. It is done thanks to PowerGood ouput signals and Enable input pin.
Also, synchronous output clock is connected to clock input of next LMZ IC.
All these signals are referenced to analog ground.
Datasheet recommends to isolate analog ground (AGND) and power ground (PGND).
Could you give me your recommendations about how to connect analog grounds between the 3 LMZ IC?
Connect all the 3 AGND together (solution 1)
or isolate the 3 AGND (solution 2).
Moreover +5VL and +1.8V are referenced to GND. Do you think I should filter the INH input signal which is referenced to AGND? Or should I create a general GROUND plane which would connect AGND and PGND pins together?