Analog line driver with adaptive impedance matching

A new principle for an adaptive line driver is presented. This type of line driver can adapt its output impedance automatically to the applied load. This results in automatically corrected output impedance for different cables with terminations. Also, the line-driver output impedance becomes insensitive to process variations. As an example, a line driver for analog video signals has been designed. The circuit operates from a 2.4-V supply in a 0.35-/spl mu/m CMOS technology. The realized circuit adapts between 38 and 85 /spl Omega/ loads, has total harmonic distortion of <-50 dB at 1.2 V/sub pp/ for 0-10 MHz, 0.09-mm/sup 2/ area, and 9-mW static power consumption.