I would like to place a voltage reference for my MCU ADC. This is my first time using voltage references. I have chosen is the LM4040. It is relatively cheap and pretty good. I am getting the 3V 0.2% tolerance 100PPM variant.
Which supply should I power this from? The power tree for my circuit looks kind of like this:
5V -> 3.3V -> MCU
I have a 5V source or a 3.3V source to choose from.
I have always thought that voltage references are like LDOs with very low noise and stable output. Although I kind of understand that a very precise shunt diode will work too, I am unfamiliar with the resistor. According to the datasheet the formula is:
If I use the 5V as input with a 3V output, I would need a 2k resistor. Am I correct? Do I need to place a capacitor in parallel with this Vref?