Patent ID: 7064575

Claim:
A circuit for communicating digital output signals onto a transmission line, comprising: a first servo generating a first digital signal defining a model resistance that substantially matches a predetermined impedance of said transmission line; a second servo receiving said first digital signal and scaling said model resistance for high (VH) and low (VL) output voltage rails of said transmission line; a third servo generating a second digital signal substantially correlating said scaled model resistance to a model transistor array; and an output driver having a working transistor array adapted to be coupled to said transmission line, said output driver receiving said second digital signal and activating selected transistors of said working transistor array in accordance therewith so that said working transistor array has an impedance substantially corresponding to said scaled model resistance; wherein, said impedance of said working transistor array substantially matches said predetermined impedance of said transmission line, and a digital output signal communicated by said output driver onto said transmission line has a voltage that is substantially one-half of a desired final voltage.