A 1.5 V class AB output buffer

Most class AB push-pull output buffers have been developed for supply voltages ⩾3.0 V. Recently developed class AB buffers, which operate at a voltage supply lower than 3.0 V, use sophisticated feedback circuits to control the quiescent current. In this paper, a simple class AB buffer is proposed. It can be used at 1.5 V power supply and has the capability to drive small resistive loads (<100 Ω). The circuit has been fabricated using a 1.2 μ digital CMOS process. Experimental results demonstrate that the proposed circuit provides good control over the quiescent current. The standard deviation of the quiescent current is 17%. Combined with a floating gate input stage, a rail-to-rail input/output op amp has been fabricated and tested