I am using ADUM 2250 I2C 5KV rms Isolator in my design. The VDD1 = 3.0 V DC is connected to 1st Micro controller SCL and SDA pins and VDD2 = 3.3V DC connected to 2nd Micro controller isolated SCL and SDA pins. Is it ok to use VDD1 = 3.0 V DC and VDD2 = 3.3 V DC or both should be equal ( VDD2 = 3.0V DC only) for proper functioning of ADuM 2250 IC
The VDD1 and VDD2 supplies are independent. They can be different voltages, but they do have to be within the valid power supply range. This is 3.0V to 5.5V for both sides of the ADuM2250. So 3.0V is fine, but when power supply tolerances need to be considered, a 3.0V nominal supply may be dropping out of the valid power supply range.