LM66100: LM66100 output capacitance

Hi Per,

There is no set maximum output capacitance for LM66100. What limits you is your inrush current. There is no way of mitigating inrush current with this device and hence, during startup, a current spike may pass through the device to fill up the output capacitance. If this inrush current is not significant, you can add more output capacitance.

I would suggest keeping the output capacitance as low as possible for your application to work correctly. 

Hi Shreyas,

and thank you very much for your quick reply.

The ideal-diode is part of our power-supply, where the ideal-diodes are used for selection of different power supplies.

i assume that the problem may be at startup, i.e. when the output capacitor is to be charged.

Would you recommend a 1uF, 4.7uF, 10uF or 22uF output capacitor? My problem is: How large capacitance can I add to the output.

BR Per

Hi Per,

As stated, the maximum value depends on your system. What minimum output capacitance does your system need to function correctly? What is your system voltage? Does the input voltage ramp up slow or is it "hotplugged"? 

All these factors contribute to the inrush current seen and so I would recommend using the smallest possible output capacitance that you can for your use case to function correctly.

Hi again,

We need at least an output capacitance of 4u7. Maybe we can manage with a 1uF !!

We have 3 input supply voltages, and the one which I think will be the problem here, is the VBUS (4.5 - 5.5V) USB supply.

If the USB supply is connected to ex. a power-bank capable of more than 2A delivery, what will then happen during power-up?

Think we can look at the USB supply as "hotplugged".

BR Per