Cascode amplifier integrated circuit with reduced miller capacitance at an output buffer stage during a transient fall response

摘要

A cascode amplifier integrated circuit (IC) with a relatively fast transient fall response (i.e., short transient fall response time) and, therefore, relatively fast operation. The cascode amplifier IC includes a bias input terminal configured to receive a bias potential V_b, a power supply input terminal configured to receive a power supply voltage V_cc, an input signal terminal configured to receive an input voltage signal V_in, and an output signal terminal. The cascode amplifier IC also includes a gain stage circuit with a plurality of interconnected bipolar transistors and an output buffer stage circuit configured. The cascode amplifier integrated circuit further includes a discharge circuit configured to discharge stray capacitance at a node of the output buffer stage circuit. The discharge circuit includes, for example, a bipolar discharge transistor (configured, for example, as an emitter-follower device) that reduces the Miller capacitance across the base and collector of one of the interconnected bipolar transistors of the output buffer stage circuit during a transient fall response. The discharging of the stray capacitance by the discharge circuit decreases the transient fall response time of the cascode amplifier IC and, thereby, increases its operation speed (that is, the discharge circuit provides for fast operation).