An electrically adjustable 3-terminal regulator with post-fabrication level-trimming function

This paper describes a new technique for 3-terminal regulators to adjust the output voltage level without additional terminals or extra off-chip components. By applying a serial control pattern using the intermediate voltage level between the supply voltage and the regulator output, the adjustment data in the internal nonvolatile memory are safely updated without noise disturbance. In an on-board test with a chip fabricated using a 0.35-µm standard CMOS process, we confirm successful output voltage adjustment with sub-10mV precision.