Voltage sequencing on power up
Many regulators have an Enable pin. You can connect the output of DVDD's regulator to AVDD's Enable to ensure it powers up afterwards. The data sheet of the regulators will indicate at what voltage (at Enable) the regulator will turn on. You can use this info to time their power up. If the timing of their power up is not satisfactory using DVDD directly, you can modify the timing of the voltage at Enable using something like a voltage divider or a capacitor.