I'm working on a volume control board based on PGA2311. I originally planned to power the MCU together with PGA VD+ from standby transformer and VA+ from a main transformer which is controlled by a relay but datasheet stated that difference beetween VD+ VA+ must be within +/- 0.3V. Does it mean that I cannot power up VD+ first and then VA+?
Maybe I should switch to PGA2310 which doesn't have difference beetween VD+ and VA+ voltages specified?
Maybe I should switch to PGA2310 which doesn't have difference beetween VD+ and VA+ voltages specified?
It normally means you power them from the same supply but have noise filtering inductor/ferrite between them to keep digital noise out of analog rail. Or run two identical voltage regulators one to each supply so they are always powered up together. The 0.3V is when internal protection diodes start to conduct - they are not normally designed for significant current so its important not to fry them.
I made some test and if only VA+ is powered, then some current leaks to VD+ and there can be seen voltage at around 3V. Fortunatelly PGA didn't get burned after that. Diode test from multimeter gave me 0.7V in both directions, so protective diodes are present.
In a datasheet from CS3310 resistor 10R is recomended beetween VA+ and VD+, there's also note that VA+ must be powered prior to VD+.
In a datasheet from CS3310 resistor 10R is recomended beetween VA+ and VD+, there's also note that VA+ must be powered prior to VD+.
