DIFFERENTIAL TERMINATION WITH INTERNAL COMMON-MODE TERMINATION VOLTAGE GENERATING CIRCUIT AND ATTENUATION CIRCUIT NETWORK

摘要

PROBLEM TO BE SOLVED: To make direct current zero at an input node of a circuit network 60 and optimize a dynamic range of a differential amplifier 88. SOLUTION: A differential termination and an attenuator circuit network 60 have an internal termination voltage generating circuit 61, and first and second termination resistors 68 and 70 are parallely connected to corresponding resistive attenuator circuits 84 and 86. A monitor circuit 66 is connected to an input node of the circuit network 60 and generates an output voltage indicating a combination of a direct common-mode voltage VCMand an internal termination voltage VTERMat the input node. A control circuit 80 generates a scale-adjusted termination voltage VT, a compensation voltage VA, and a corresponding drive current through the use of the internal termination voltage VTERMand an output signal VIof the monitor circuit, and they optimize a dynamic range of the differential amplifier 88. The internal termination voltage generating circuit 61 receives termination voltage parameters from a measuring device and generates an internal termination voltage. COPYRIGHT: (C)2006,JPO&NCIPI