POTx REFERENCE

• The voltage reference is based on the TL1431 (an adjustable precision shunt reference)
• The voltage is set by a pair of resistors such that Vref = 2.5V * (1 + Ra/Rb)
• A weakness of the shunt reference is that the available current is dependent on many parameters including supply voltage, reference voltage, and reference shunt resistors. The shunt reference also uses the maximum design current at all times - even if there is no load current.

POT4 and POTa are built with a reference voltage of 9.85V using RR2 of 7.32K and RR3 of 2.49K.