Is it important to not exceeded the capacitance of 2.2 µF for the internal regulator of an STM32F722xx MCU?
On page 109/230 of the STM32F722xx datasheet (I use the STM32F723VE) it says that the capacitance of the external capacitor that is stabilizing the internal main voltage regulator should be 2.2 µF. We use 0603 capacitors (metric; so 0201 imperial) which are rated for 6.3 V (board is running at 3.3 V). All the other capacitors on the board are 1.0 µF as well as 4.7 µF and in order to consolidate the BOM I was wondering whether I could replace that 2.2 µF with 4.7 µF. (In the comments someone suggested using two 1.0 µF capacitors instead of one 4.7 µF capacitor, which is a good idea.) I have a voltage regulator for the 5V of USB on the board as well, and for that regulator I use the 1.0 µF that the datasheet calls for, in order to not mess with USB:
"The final thing is USB specs though. It only allows for 10uF at the device input to limit surge current. Using a 10uF at the input and another 10uF at the output of the regulator could easily exceed allowable USB ratings. Also the high capacitance at the USB inlet port can cause significant voltage spikes and ringing when cable is plugged in unless dampening is taken care of, so be careful about the design."
Can I use 4.7 µF instead of 2.2 µF for the internal regulator of the STM32F722xx series or is that a bad idea?
