Common-mode stabilization of high-frequency differential distributed driver amplifier
AssigneeCiena Corporation
InventorsJeffrey Henry Bennett, Aref Pourzadi
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Abstract
Aspects of the subject disclosure may include, for example, a common emitter stage having a differential input configured to receive an input signal from an input transmission line, a common base stage coupled with the common emitter stage and having a differential output configured to provide a differential output signal to an output transmission line, and a biasing network to bias the common base stage, the biasing network including components selected to limit common mode gain of the common base stage at relatively high frequencies of interest without affecting a differential mode gain of the common base stage. Other embodiments are disclosed.
Claims20
An amplifier circuit, comprising:
- a common emitter stage having a differential input configured to receive an input signal from an input transmission line;
- a common base stage coupled with the common emitter stage and having a differential output configured to provide a differential output signal to an output transmission line;
- and
- a biasing network to bias the common base stage, the biasing network comprising a resistive element coupled between a common node of the common base stage and a ground node.
A distributed differential amplifier, comprising:
- a plurality of gain stages, a gain stage of the plurality of gain stages comprising:
- a cascode amplifier configured to receive a differential input signal at a differential input and to provide a differential output signal at a differential output;
- and
- a biasing network, the biasing network including a resistive element coupled between a common node of the cascode amplifier and a ground node to improve stability of the gain stage at relatively high frequencies of operation.
A distributed amplifier circuit, comprising:
- a plurality of gain stages, a gain stage of the plurality of gain stages comprising:
- a first amplifier stage having a differential input configured to receive a differential input signal from an input transmission line, wherein the differential input signal comprises common mode signals and differential mode signals across a band of operating frequencies;
- a second amplifier stage coupled to the first amplifier stage and having a differential output configured to provide a differential output signal to an output transmission line, the first amplifier stage and the second amplifier stage cooperating to provide a common mode gain for the common mode signals and a differential mode gain for the differential mode signals;
- and
- a biasing circuit coupled to the second amplifier stage, the biasing circuit including a resistive element coupled between a common node of the second amplifier stage and ground, the resistive element selected to limit the common mode gain at relatively high frequencies of the band of operating frequencies without affecting the differential mode gain.
Dependencies are inferred from the claim text.