A differential termination and attenuator network having an automated
common mode termination voltage generator includes first and second
termination resistors coupled in parallel with corresponding resistive
attenuator circuits. A monitoring circuit coupled to input nodes of the
network generates an output signal representative of the combination of a
DC common mode voltage on the input nodes and an adjustable termination
voltage. A control circuit generates scaled termination and compensation
voltages and associated drive currents using the adjustable termination
voltage and the monitoring circuit output signal. The scaled termination
voltage and the scaled compensation voltage operate on the differential
termination and attenuation network to optimize the dynamic range of a
differential amplifier connected to the first and second attenuator
outputs. An automated termination voltage generator automatically adjusts
the adjustable termination voltage to match the DC common mode input
voltage, which nulls the DC currents at the input nodes.