I need 8 digital outputs and 1 analog input fpr my project. The digital output need to drive relays (no more than two will be operating at any one time ) that require 5V and 20 mA. I was wondering if I could use an analog output ( put output to 5V ) to provide power to the digital outputs
or could I draw power from elsewhere on the board
You can’t use the analog output as a source for 20mA. There is a 1.5k series resistors at the analog outputs. The max current is about 1.5mA when short circuited.
Instead you can use the pin header SK2 or SK3 to get the USB +5V.
The second pin of these pin headers are connected directly to the PC’s USB connector’s +5V.
It should be no problem to take 40mA from this +5V source.
Thanks for the help, I’ll try youe suggestion