I have a little confusion about 278 power supply. It is given by the datasheet on page 3 that VDD ranges from 4.75V to 5.25V. But on the page 5 Table 3- pin function description, VDD, VDD2,VDD3 is descibed the range of 3.5V~6V. So what it is difference and which one should i refer to? Besides, is it possible that these three pins are powered with different voltage, for example Vdd with 5V, VDD2 or VDD3 with 4V?