A widely tunable Gm-C filter using tail current offset in two differential pairs. - Tomoyuki Tanaka; Sungwoo Cha; Shinsaku Shimizu; Tsukasa Ida; Hiroaki Ishihara; Toshimasa Matsuoka; Kenji Taniguchi 001; Akashi Sugimori; Hiroki Hihara (ISCAS (1), 2005)