Techniques for designing wide band low noise amplifiers
AssigneeAgere Systems Inc.
InventorsTienyu Chang, Jinghong Chen
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Abstract
A wideband amplifier having an amplifier input terminal and an amplifier output terminal includes at least one transistor coupled to the amplifier input terminal and an impedance element coupled between the amplifier input terminal and the amplifier output terminal. A feedback signal is transmitted between the amplifier output terminal and the amplifier input terminal by way of the impedance element wherein the feedback signal varies in accordance with changes in an impedance of the impedance element so as to peak a frequency response of the amplifier.
Claims35
A wideband amplifier having an amplifier input terminal and an amplifier output terminal, comprising:
- at least one transistor coupled to said amplifier input terminal;
- at least first and second impedance elements coupled between said amplifier input terminal and said amplifier output terminal;
- and
- a feedback signal path comprising the at least first and second impedance elements and operative to convey a feedback signal transmitted between said amplifier output terminal and said amplifier input terminal by way of said first and second impedance elements, wherein said feedback signal varies in accordance with changes in an impedance of each of said first and second impedance elements as a function of a frequency of an input signal applied to the amplifier input terminal, a value of each of said first and second impedance elements being adapted so as to peak a frequency response of said amplifier;
- wherein said at least one transistor comprises an input transistor having a transistor input terminal, wherein the amplifier further comprises a transistor feedback loop coupled to said input transistor to provide said feedback signal, said feedback loop comprising a feedback resistor and a feedback capacitor, said feedback resistor and said feedback capacitor being coupled in parallel with each other.
A wideband amplifier having an amplifier input terminal and an amplifier output terminal, comprising:
- at least one transistor coupled to said amplifier input terminal;
- an impedance element coupled between said amplifier input terminal and said amplifier output terminal;
- and
- a feedback signal transmitted between said amplifier output terminal and said amplifier input terminal by way of said impedance element wherein said feedback signal varies in accordance with changes in an impedance of said impedance element so as to peak a frequency response of said amplifier;
- the amplifier further comprising a differential amplifier circuit having first and second amplifier input terminals adapted to receive first and second input signals, respectively, to be amplified by said differential amplifier circuit;
- and
- first and second input transistors including first and second transistor input terminals, respectively;
- wherein said first and second input transistors each have a gate and a drain further comprising first and second capacitors wherein each of said first and second capacitors couples said gate of one of said first and second input transistors to said drain of the other of said first and second input transistors.
A wideband amplifier having an amplifier input terminal and an amplifier output terminal, comprising:
- at least one transistor coupled to said amplifier input terminal;
- an impedance element coupled between said amplifier input terminal and said amplifier output terminal;
- a feedback signal transmitted between said amplifier output terminal and said amplifier input terminal by way of said impedance element wherein said feedback signal varies in accordance with changes in an impedance of said impedance element so as to peak a frequency response of said amplifier;
- a differential amplifier having first and second input transistors each of said first and second input transistors having a gate and a drain;
- first and second input signals to be amplified by said differential amplifier circuit wherein said first and second input signals are received by said gates of said first and second input transistors;
- and
- first and second capacitors wherein each of said first and second capacitors couples said gate of one of said first and second input transistors to said drain of the other of said first and second input transistors.
Dependencies are inferred from the claim text.