Chris03/10/2023, 8:41 PM
Boris Murmann03/10/2023, 8:48 PM
Luis Henrique Rodovalho03/10/2023, 9:51 PM
Chris03/10/2023, 9:52 PM
analysis and yes there is an RHP zero ~ 3.7e4 Hz canceled with an LHP pole ~ 2.8e4 Hz. I further verified their stability in transient analysis and yes the second situation circuit oscillated. Guess I need to push that RHP zero to the left plane somehow. More often I see a zero-pole pair (or doublet in closed-loop) as an LHP pole + an LHP zero but not with an RHP zero. Miller compensation without a null resistor generates an RHP zero, parasitic Cgd has a RHP zero; are there in general other situations where this LHP pole + an RHP zero occurs? Thanks.
Luis Henrique Rodovalho03/10/2023, 9:56 PM
Boris Murmann03/11/2023, 12:19 AM
Chris03/11/2023, 12:32 AM
installed). The first schematic is EA, the second one is EA with the PMOS pass transistor, and the last one is the loop stability testbench of the LDO. In the pictures I attached before, the first one is at which the load current is 10mA and the second is load current=10uA. It has a stability problem when the load current is small. Sorry if those wire connections are messy as I am still changing things back and forth.
Boris Murmann03/11/2023, 12:38 AM
Chris03/11/2023, 1:13 AM
Boris Murmann03/11/2023, 1:19 AM
Chris03/11/2023, 1:31 AM
Boris Murmann03/11/2023, 1:44 AM
Luis Henrique Rodovalho03/11/2023, 7:33 AM
Boris Murmann03/11/2023, 2:48 PM