Hi Team,
LP5907's PSRR is shown in the below. Its test condition is: 3.7V-->2.8V.
I want to know if test condition(Vin/Vout) changes, will the PSRR become better or worse?
For example, if 3.4V-->3.3V/50mA, what is PSRR @100kHz? Still less than -60db?
Thanks!
BR
Marvin
Hi Marvin,
In general the PSRR will be the same or very similar if you use the same headroom/Vdo (Vin-Vout) and load current. I've attached a quick ppt which shows what conditions (Vin, Vout, Iout, Cout, etc...) have a significant effect on PSRR and which don't.
Now for your use case you are asking about a significantly lower headroom (100mV compared to the 900mV in the datasheet), so this is going to significantly change the PSRR. I don't have any PSRR data with that exact condition however below is a PSRR plot which is close, it is using 80mA and your use case is 50mA. I'd estimate that your performance would be similar to the RED 200mV line shown in the graph below since you are using a lower current.
