A 3-V CMOS low-distortion class AB line driver suitable for HDSL applications

A fully differential CMOS line driver for use in high bit-rate digital subscriber line (HDSL) services Is presented. The circuit is fabricated in a single-poly quad metal 0.35-/spl mu/m process and achieves <-70-dB total harmonic distortion while driving up to /spl plusmn/2.4-V, 200-kHz signals into 30 /spl Omega/ with a 3-V supply. The circuit features a closed loop gain of 6.0 with minimal input capacitance (<200 fF). The circuit requires less than 20 mA of quiescent current and is capable of delivering dynamic currents as large as 180 mA. The circuit is a multistage amplifier utilizing nested-Miller compensation and an enhanced class AB output stage.