# US 8,786,368 B2 · Distributed amplifier with improved stabilization > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,368 B2 - Document ID: US8786368B2 - Status: Granted - Kind: B2 - Application number: 13/385,772 - Filed: 2012-03-06 - Published: 2012-09-13 - Granted: 2014-07-22 - Earliest claimed: 2011-03-09 - Assignees: Hittite Microwave Corporation - Applicants: Keith Benson - Inventors: Keith Benson - Web page: https://patentgrep.com/patent/US8786368B2 ## CPC - H03F 1/18: by use of distributed coupling {, i.e. distributed amplifiers (distributed amplifiers using coupling networks with distributed constants H03F3/605)} - H03F 1/086: {with FET's} - H03F 1/223: {with MOSFET's} - H03F 1/42: Modifications of amplifiers to extend the bandwidth - H03F 3/19: with semiconductor devices only - H03F 3/193: with field-effect devices (H03F3/195 takes precedence) - H03F 3/607: {using FET's} - H03F 2200/108: A coil being added in the drain circuit of a FET amplifier stage, e.g. for noise reducing purposes - H03F 2200/144: the feedback circuit of the amplifier stage comprising a passive resistor and passive capacitor - H03F 2200/153: Feedback used to stabilise the amplifier - H03F 2200/267: A capacitor based passive circuit, e.g. filter, being used in an amplifying circuit - H03F 2200/423: Amplifier output adaptation especially for transmission line coupling purposes, e.g. impedance adaptation - H03F 2200/61: the cascode amplifier has more than one common gate stage - H03F: AMPLIFIERS ## Abstract A distributed amplifier with improved stabilization includes an input transmission circuit, an output transmission circuit, at least one cascode amplifier coupled between said input and output transmission circuits. Each cascode amplifier includes a common-gate configured transistor coupled to the output transmission circuit, and a common-source configured transistor coupled between the input transmission circuit and the common-gate configured transistor. The distributed amplifier also includes a non-parasitic resistance and capacitance coupled in series between a drain and a gate of at least one of the common-gate configured transistors for increasing the amplifier stability. ## Claims ### Claim 1 A distributed amplifier with improved stabilization, comprising: an input transmission circuit; an output transmission circuit; at least one cascode amplifier coupled between said input and output transmission circuits, each cascode amplifier including a common-gate configured transistor coupled to the output transmission circuit, and a common-source configured transistor coupled between the input transmission circuit and the common-gate configured transistor, each cascode amplifier further including one or more additional common-gate transistors DC-coupled between each of the common-gate configured transistors and common-source configured transistors; and an amplifier stability a feedback network including a non-parasitic resistance and capacitance coupled in series between a drain and a gate of at least one of the common-gate configured transistors for increasing the amplifier stability. ### Claim 2 (depends on 1) The distributed amplifier of claim 1 in which the drains of each of the common-gate transistors are coupled together and the gates of each of the common-source configured transistors are coupled together. ### Claim 3 (depends on 1) The distributed amplifier of claim 1 in which the resistance and the capacitance of each feedback network includes a resistor and a capacitor coupled in series across the gate and drain terminals of at least one of the one or more additional common-gate configured transistors. ### Claim 4 (depends on 3) The distributed amplifier of claim 3 in which each resistor has a value of approximately 800 ohms and each capacitor has a value of approximately 1 pF. ### Claim 5 (depends on 3) The distributed amplifier of claim 3 in which each resistor has a value in a range of between 20 ohms to 10K ohms. ### Claim 6 (depends on 3) The distributed amplifier of claim 3 in which each capacitor has a value in a range of between 0.1 pF to 10 pF. ### Claim 7 (depends on 1) The distributed amplifier of claim 1 in which each of the common-gate configured transistors include a non-parasitic resistance and capacitance coupled between its corresponding drain and gate. ### Claim 8 (depends on 1) The distributed amplifier of claim 1 in which there is only one cascode amplifier coupled between said input and output transmission circuits. ### Claim 9 A distributed amplifier with improved stabilization, comprising: an input transmission circuit; an output transmission circuit; at least two cascode amplifiers coupled between said input and output transmission circuits, each cascode amplifier including a common-gate transistor coupled to the output transmission circuit, and a common-source transistor coupled between the input transmission circuit and the common-gate transistor; and a feedback network including a resistor and capacitor coupled between a drain and a gate of at least one of the common-gate transistors for increasing the stabilization of at least one common-gate transistor. ### Claim 10 (depends on 9) The distributed amplifier of claim 9 in which each cascode amplifier further includes a second common-gate transistor coupled between the common-gate and common-source transistors. ### Claim 11 (depends on 9) The distributed amplifier of claim 9 in which each of the common-gate transistors include a resistor and capacitor coupled between its corresponding drain and gate. ### Claim 12 (depends on 9) The distributed amplifier of claim 9 in which there are between and including four and ten cascode amplifiers coupled between said input and output transmission circuits. ### Claim 13 (depends on 9) The distributed amplifier of claim 9 in which each resistor has a value of approximately 800 ohms and each capacitor has a value of approximately 1 pF. ### Claim 14 (depends on 9) The distributed amplifier of claim 9 in which each resistor has a value in a range of between 20 ohms to 10K ohms. ### Claim 15 (depends on 9) The distributed amplifier of claim 9 in which each capacitor has a value in a range of between 0.1 pF to 10 pF.