A 0.028% THD+N, 91% power-efficiency, 3-level PWM Class-D amplifier with a true differential front-end. - Sunwoo Kwon; Injeong Kim; Shinyoung Yi 002; Sangheyub Kang; Sangheon Lee; Taeho Hwang; Byoungkwon Moon; Yunyoung Choi; Hosung Sung; Jinseok Koh (ISSCC, 2012)