Charge-pump assisted low-power/low-voltage CMOS op amp design

Low-voltage/low-power requirements have become essential considerations in modern mixed-signal designs. In this paper, we present a 1.8 V multi-stage opamp designed using a standard 0.6 /spl mu/m n-well CMOS process. The op amp designs include a new high efficiency DC-DC converter used in a low-voltage frequency compensation configuration that tracks process, temperature, and supply voltage variations and enables accurate pole-zero cancellation. Low-power operation is compared in passive and active g/sub m/ feedforward compensation techniques. An automatic threshold calibration scheme is also described.