LM22672: 5V turn-on inrush

Hello,

Looking at the startup waveform it is rather odd from what I am used to see. Looking at EVM, that seems to be a "jump" in the output voltage rather than a linear ramp, which is causing that in rush.

Figure 2

What you are seeing I believe is reflective of the device's actual performance.

I will see if anyone on the team know how to minimize the inrush.

Thank you for the quick response and suggestion. Let me try this change and update you.

You are welcome. Let me know how it goes.

Added 100pF CFF. It helps a bit to reduce peak current by 40mA. Not sure how this will affect the stability of the regulator.

As you mentioned above, this regulator jumps output voltage at startup per figure 2 of EVM. I am surprised TI did not put this waveform on the datasheet. 

Hello Nik,

The cff will introduce a pole zero pair. A modest Cff of 100pF should be OK, but, I would look at the load transient response to get a feel for the stability of the converter. I imagine, the load transient maybe a bit slower due to increased phase margin.