a method and structure for a driver circuit having a plurality of parallel resistors , where a total impedance of all the resistors equals an impedance of an associated transmission line and a switch adapted to combine the resistors to control an output level of the driver . the driver circuit &# 39 ; s switch selectively connects the resistors to either a voltage high signal or a voltage low signal . the first set of the switches connect a voltage high signal to a first resistor of the resistors and a second set of switches connect a voltage low signal to a second resistor of the resistors . the switch has a matched pair of opposite type transistors . the driver circuit has balancing resistors connected to the switch , the balancing resistors are sized to balance the resistance within the driver circuit . the resistors are the balancing resistors and the drivers are connected to the switches .