A new full CMOS 2.5 V two-stage line driver with variable gain for ADSL applications

In this paper a new low-voltage two-stage class-AB line driver for ADSL applications is presented. The new proposed line-driver consists of only two stages with a new method to control the quiescent current of the output stage. The low-voltage full-CMOS high-linear line driver shows -77 dB THD for a load as low as 20 ohms. The line driver has variable gain, attenuating the input signal from 0 dB to -14 dB with 2 dB steps. The peak to peak differential output swing is 4.2 V from a 2.5 V supply voltage in a 0.25 /spl mu/m standard CMOS technology.