Please I’d like to ask what is the recommended bulk capacitance for robust operation that shall be placed on custom made carrier board for SYS_VIN_HV and SYS_VIN_MV supply voltages?
We tried to implement similar values as on B03 carrier board. It was not that easy to get oriented in the schematic what all caps counts to SYS_VIN_HV and SYS_VIN_MV bulk capacitance, so we maybe missed something.
At the moment we have about:
- about 300uF on SYS_VIN_HV
- more than 350uF on SYS_VIN_MV
- another more than 300uF on the supply input to our carrier board (de-facto direct connected to SYS_VIN_HV and input caps to SYS_VIN_MV buck converter)
I have to admit that at them moment we noticed occasional quite deep voltage drops on both SYS_VIN_HV (up to 2V) and SYS_VIN_MV (up to 3V). Voltage drops happens with occurrence in seconds to few seconds (but not periodically) and seems to be related to SoM module operation (ie even during booting). This supply voltage drops sometimes leads to some erratic behavior or reset of the SoM (especially when operating closer to lower input voltage range ~9V)
Are our bulk capacitors values reasonable or shall we consider adding more?