A 10-kA cm 2 Nb AlO Nb junction technology for rapid single flux quantum (RSFQ) integrated circuits has been developed. Modifying our standard 1.6-kA cm 2 cell library, we have implemented elementary cells used to build RSFQ digital-to-analog converters for ac voltage standard applications. The 10-kA cm 2 library cells have been fabricated by utilizing existing process tools. Correct operations of the circuits have been confirmed at low speed. The maximum operating frequencies evaluated by an average-voltage measurement technique were consistent with the scaling rules of RSFQ circuits.Index Terms-Cell library, digital-to-analog converter, high critical current density, rapid single flux quantum, superconductor integrated circuit.