A 0.9-V 28-MHz Highly Digital CMOS Dual-RC Frequency Reference With ±200 ppm Inaccuracy From -40 °C to 85 °C. - Choi, Woojun; Angevare, Jan A.; Park, Injun; Makinwa, Kofi A. A.; Chae, Youngcheol (IEEE J. Solid State Circuits, 2022)