Analog multiplexer circuit having an active load circuit functioning commonly for a plurality of bipolar differential amplifying input circuits

Abstract

An analog multiplexer circuit comprising bipolar differential amplifying input circuits, an active load circuit, a selector circuit, an emitter-grounded circuit, and a switch circuit. Differential analog signals are supplied to each of the input circuits. The active load circuit functions commonly for the input circuits. The selector circuit selects one of the input circuits in accordance with a selection signal. The emitter-grounded circuit is used to output the differentially amplified signal generated by the differential amplifying circuit constituted by the selected input circuit and the active load circuit. The switch circuit is inserted between the active load circuit and one of the input circuits and is turned on and off by the selection signal. When the one of the input circuits is not selected, the switch circuit is off, thus electrically disconnecting the one of the input circuit from other input circuit. When the one of the input circuits is selected, the switch circuit is on, thus electrically connecting the one of the input circuit and the active load circuit.

Dependencies are inferred from the claim text.