i need a -1.25V voltage reference which also tracks the VSS.in my case vss is -2.5.actually i need to convert this voltage reference to current reference using v-i converter.now one terminal of resistor is vref(-1.25) and other terminal is vss(-2.5). thats why i need a vref that also tracks the vss so that voltage across the resistor do not change so that i get constant current.
now my question is that is there any vref available in market ,or there is any another way out to generate constant current.