Field effect transistor current mode logic with changeable bulk configuration of load transistors

A field effect transistor current mode differential logic circuit comprising load transistors for converting the current output of each differential leg current to voltage output, and means for configuring the bulk of each differential leg's load transistor to be connected to the drain of the load transistor for use the logic circuit in Subthreshold Source Coupled Logic (STSCL) mode, and means for configuring the bulk of each leg load transistor to be connected to a voltage or to source of the same transistor for use in MOS current more logic (MCML) operation.