Disclosed is a reference circuit having an even number m of groups of m parallel-connected magnetic tunnel junctions (MTJs). The MTJs in half of the groups are programmed to have parallel resistances (RP) and the MTJs in the other half are programmed to have anti-parallel resistances (RAP). Switches connect the groups in series, creating a series-parallel resistor network. The total resistance (RT) of the network has low variability and is essentially equal to half the sum of a nominal RP plus a nominal RAP and can be employed as a reference resistance (RREF). Under specific biasing conditions the series-parallel resistor network can generate a low variability reference parameter (XREF) that is dependent on this RREF. Also disclosed are an integrated circuit (IC) that includes the reference circuit and a magnetic random access memory (MRAM) structure, which uses XREF to determine stored data values in MRAM cells and associated methods.