Bandwidth improvement for amplifiers
AssigneeFujitsu Limited
InventorNikola Nedovic
Life of this patent
Estimating the term…
Abstract
A circuit may include an amplifying circuit and a t-coil inductor. The amplifying circuit may include an input node, an output node, an amplifier, and a feedback loop. The feedback loop may be coupled between the input node and the output node. The amplifying circuit may be configured to receive a current signal on the input node and to output a voltage signal based on the current signal on the output node. The t-coil inductor may include a first portion and a second portion. A first node of the first portion may be coupled to the input node of the amplifying circuit and the second portion may be included in the feedback loop.
Claims16
A circuit comprising:
- an amplifying circuit including an input node, an output node, an amplifier coupled between the input node and the output node, and a feedback loop coupled between the input node and the output node, the amplifying circuit configured to receive a current signal on the input node and to output a voltage signal based on the current signal on the output node;
- and
- a t-coil inductor including a first node, a second node, a third node, and a continuous conductive layer coupled between the first node and the second node, wherein the third node is coupled to the continuous conductive layer between the first node and the second node to define a first portion between the first node and the third node and a second portion between the third node and the second node and the third node is coupled to the input node of the amplifying circuit and the second portion is included in the feedback loop.
An integrated circuit comprising:
- a pad configured to couple the integrated circuit to a trace outside the integrated circuit;
- a transimpedance amplifying circuit including an input node, an output node, an amplifier coupled between the input node and the output node, and a feedback loop coupled between the input node and the output node;
- and
- a t-coil inductor including first, second, and third nodes, and a continuous conductive layer coupled between the first node and the third node, wherein the second node is coupled to the continuous conductive layer between the first node and the third node to define a first portion between the first node and the second node and to define a second portion between the second node and the third node, wherein the second node is coupled to the input node of the transimpedance amplifying circuit, the third node is coupled to the pad, and the first node is within the feedback loop such that the first portion is included in the feedback loop.
A method of improving a bandwidth of an amplifying circuit, the method comprising:
- extending a transimpedance bandwidth of a transimpedance amplifying circuit that includes an amplifier and a feedback loop by coupling a first portion of a t-coil inductor into the feedback loop;
- extending an input impedance bandwidth of the transimpedance amplifying circuit by coupling a first node of a second portion of the t-coil inductor to an input node of the transimpedance amplifying circuit;
- and
- selecting an inductance of the first portion of the t-coil inductor to be more than an inductance of the second portion of the t-coil inductor such that an effective inductance of the first portion of the t-coil inductor at operating frequencies of the amplifying circuit is approximately equal to the effective inductance of the second portion of the t-coil inductor at operating frequencies of the amplifying circuit.
Dependencies are inferred from the claim text.