Adafruit precision voltage reference lm4040 breakout 2 048v and 4 096v adafruit 2200 p the adafruit precision voltage reference gives you 2 x high precision voltages which are accurate to 0 1 a great little gadget for measuring the accuracy and precision of your microcontroller s analogue to digital converter adc or providing a good solid reference for analogue conversion simply apply 5 to 12v if you want to use both references or 3v if you only need the 2 048v reference they are o