Patent ID: 7164994

Claim:
A differential termination and attenuator network having an internal common mode termination voltage generator receiving a DC common mode voltage from a voltage source having source resistances and coupled to a differential amplifier comprising: an internal common mode termination voltage generator receiving termination voltage parameters from an external source and generating an internal termination voltage; first and second input termination resistances having a common node and respective input nodes receiving the DC common mode voltage from the voltage source; first and second attenuators having a common node and respective input nodes and output nodes with each respective input node coupled to one of the first and second input termination resistances; a monitoring circuit coupled to the input nodes of the first and second input termination resistances for generating an output signal representative of the combination of the DC common mode voltage on the input source resistances and a voltage representative of the internal termination voltage on the input termination resistances; and a control circuit receiving the internal termination voltage and the monitoring circuit output signal and generating a scaled termination voltage and drive current and a scaled compensation voltage and drive current that are a function of the internal termination voltage and the DC common mode voltage with the scaled termination voltage and drive current coupled to the common node of the first and second input termination resistances and the scaled compensation voltage and drive current coupled to the common node of the first and second attenuators for providing DC currents through the first input termination resistance and first attenuator and the second input termination resistance and second attenuator for nulling DC currents at the input nodes of the first and second input termination resistances and provides a DC common mode voltage at the output nodes of the first and second attenuators for optimizing the dynamic range of the differential amplifier.