LP5907-Q1: Powering a circuit with higher capacitance?

Hello,

The datasheet for LP5907-Q1 recommends an output capacitor in the range 1uF ~ 10uF. That's not to say that it won't work/be stable with COUT ≈ 140uF; I just don't have any data to share so I don't know whether it will work. Hence, I cannot recommend using LP5907-Q1 for this application. 

In regards to the question about the ferrite bead, my understanding is that the ferrite bead will be connected to the LDO output, and then after the ferrite bead is where the output caps will be. Is that correct? If so, I would be concerned with the inrush current causing a large voltage spike at the output. This conclusion isn't specific to the LP5907-Q1; I don't think the ferrite bead should be connected before the output capacitors for any LDO.

Regards,

Nick

Dear Nick,

Many thanks for the prompt answer! 
A picture says a thousand words, so here is an excerpt of the said circuit:

Hello,

I see. The configuration looks better than I was thinking, but I would still be concerned with inrush current to the extra capacitor bank to cause a large inductive spike during startup. A device with a soft-start feature would really help to alleviate this issue.

Regards,

Nick

Hello Nick,

Fair enough. I suppose then an IC such as the TPS7A20 would be quite suitable? The datasheet mentions an output capacitance of up to 200uF.

Thanks and regards,
Emil-Radu

You as well!