A memory device can include a plurality of memory cells formed in a substrate, each having a resistive element programmable between at least two different resistance states, including memory cells configured to store data received by the memory device, and reference cells; a reference circuit formed in the substrate configured to generate at least a first reference resistance from resistances of a plurality of reference cells; a sense circuit formed in the substrate coupled to the memory cells and at least the first reference resistance and configured to compare a resistance of a selected memory cell to at least the first reference resistance to determine the data stored by the selected memory cell.