Can I increase the output capacitance of a DCDC beyond the specified maximum?

The MPM3822C is a synchronous, step-down, power module with an integrated inductor.

According to the datasheet, the maximum output capacitance is 100uF:

Questions:

• Why do they specify a maximum?
• Would it be bad if I used two 100uF capacitors?
• The maximum has to do with the stability of the feedback loop in the regulator. It is designed to be stable up to a certian output capacitance value only. If you use two 100 uF caps, that begaves the same as one 200 uF cap. So you would be exceeding the maximum and you risk instability. Also, explain why 100 uF is not enough for you. Dec 15, 2021 at 17:44
• @Bimpelrekkie - This is powering a chip with a fairly narrow voltage window. We are currently getting some intermittent faults on the board, and I'm not sure where they're coming from. One thing I wanted to try was to reduce the power supply noise as much as possible, in case spikes were bringing the voltage out of spec for a moment and causing the faults. Dec 16, 2021 at 9:57
• To determine if the power supply noise is the issue, here's what I would do. 1) Measure the current output DC voltage of this DCDC. Let's say it is 5.00 V. 2) Then connect a lab supply across the output of the DCDC so that the lab supply can power the load (instead of the DCDC). 3) Set the lab supply to a slightly higher voltage than the DCDC so in my example that would be 5.10 V. When you do that, the DCDC's feedback loop will see that the output voltage is high enough already so it will stop feeding the load. If that solves your problem then indeed supply ripple is the issue. Dec 16, 2021 at 11:23
• @Bimpelrekkie that's an interesting technique, would you mind explaining why you couldn't just let the lab supply power the load at the same voltage, with the DCDC disabled (no input) or disconnected? Or are you assuming that doing so is not practical? Dec 22, 2021 at 2:52
• why you couldn't just let the lab supply power the load at the same voltage, with the DCDC disabled If the DCDC can be disabled or removing the input voltage is OK (depends on DCDC) then sure, that can be done as well. But the method I suggest is easier to apply I think as no other changes are needed. Dec 22, 2021 at 11:02