Can more details be provided for this plot from the ADuCM310, ADuCM320(I), ADuCM322(I) datasheets?
Can the requirements be explained?
The explanation is as follows:
It is expected that the DVDD supply to the ADuCM310/32x parts will be from a 3.3V supply (+/-5%).
This supply will connect to the ADuCM310/32x via a series resistor - typically a few ohms in value.
So, there will be a voltage drop across this series resistor depending on the current consumption of the ADuCM310/32x.
ADuCM310/32x default/power on conditions:
The ADuCM310/32x default power-on reset trigger voltage is 2.85V - maximum value is 2.9V.
So, the ADuCM310/32x is not guaranteed to exit its reset state on power up until DVDD goes above 2.9V.
By default, most of the ADuCM310/32x peripherals are off - specifically the IDACs/VDACs and ADC
After Power-on - what happens?
After power-on, the internal kernel program executes and this configures the power-down voltage level (brown-out value). Typically, this is 2.79V with a maximum value of 2.83V.
This means the ADuCM310/32x will not reset itself unless the DVDD supply voltage drops below 2.83V.
Once user code begins execution, it is expected more peripherals will be enabled on the ADuCM310/32x that will cause the DVDD supply voltage to drop slightly due to the series resistor.
Once the part has exited the power-on reset state, the part can safely operate with a DVDD voltage down to 2.85V.