The pulse-driven AC Josephson voltage standard, often called “Josephson Arbitrary Waveform Synthesizer” (JAWS), is based on large series arrays of SNS (S…superconductor, N…normal metal) Josephson junctions with NbxSi1-x as barrier material. Arbitrary AC voltages can be synthesized with high spectral purity and quantum precision. Series arrays of up to 5-stacked SNS junctions [1] have been implemented with up to 60 000 junctions for a 10 mm x 10 mm chip. A sophisticated complex fabrication technology was developed to achieve a high device yield. Electron beam lithography, chemical mechanical polishing and atomic layer deposition are the key components of this technology. The arrays are operated at 4 K by short current pulses, delivered by a fast pulse pattern generator, with a maximum data rate of 30 Gbit/s. The desired output waveform is encoded by means of a higher-order sigma-delta modulation. Output voltages of more than 2 V were demonstrated at PTB by operating 16 arrays in series [2]. Recent efforts to further increase the output voltage are an optical pulse-drive [3] or an on- chip power divider [4]. Many applications in voltage metrology have been established already.