The paper reviews the circuitry of differential stages (DSs) based on the elements of radiation-hardened bipolar and field effect analog gate-array master chip "AGAMC-1.3" (OJSC "Integral", Minsk city, Belarus). It suggests architectures of op amps (OAs) realized on the base of BJTs-JFETs. Their feature lies in the absence of classical reference current source setting a steady-state behavior of the input transistors. It increases the radiation stability. The parameters of experimental circuit of OA of this class IC-3, oriented for the use in sensor systems of demanding application, are given.