This paper presents a fully integrated Hall sensor microsystem with a current-mode output. The system operates in open-loop and includes a Hall sensor with internal biasing, a fully differential front-end, a preamplifier chain and a voltage-to-current converter (V-I). The effects of the V-I block on the sensitivity drift of the system are analyzed and a current biasing of the Hall cells is proposed so that the current output feature adds no drift to the microsystem sensitivity. The whole microsystem is integrated in a 0.35μm CMOS technology. It occupies an area of 11.55mm2. The sensitivity drift of the system is characterized, and shows that the V-I does not degrade the overall sensitivity drift of the system.