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US 9,755,678 B2Granted
Low noise transconductance amplifiers
AssigneeAnalog Devices Global
InventorsSivanendra Selvanayagam, Shane A. O'Mahony, Michael J. Deeney, Niall Kevin Kearney
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Abstract
Provided herein are apparatus and methods for transconductance amplifiers, such as split cascode low-noise transconductance amplifiers (LNTAs). In an embodiment, an LNTA includes split current paths each coupled to a different mixer by way of a different alternating current (AC) coupling capacitor. The split current paths of the LNTA can be enabled during different modes of operation, such as when the input to the LNTA is within different frequency bands.
Claims20
An apparatus comprising:
- a transconductance amplifier comprising split cascode current paths, the split cascode current paths comprising a first current path from a cascode node to a first output and a second current path from the cascode node to a second output, and the transconductance amplifier is configured to receive a radio frequency (RF) input voltage, provide an RF output current to the first output in a first state, and provide the RF output current to the second output in a second state, wherein the transconductance amplifier is configured to operate in the first state at a different time than the second state;
- mixers comprising a first mixer and a second mixer;
- and
- a capacitance circuit comprising a first capacitor and a second capacitor, the first capacitor electrically coupled between the first output of the transconductance amplifier and an input of the first mixer, and the second capacitor electrically coupled between the second output of the transconductance amplifier and an input of the second mixer, the first capacitor and the second capacitor having different capacitances.
1 more element
An apparatus comprising:
- a transconductance amplifier comprising:
- an amplification circuit configured to receive a radio frequency input voltage and provide a radio frequency current;
- and
- a select circuit configured to receive the radio frequency current from the amplification circuit and to provide the radio frequency current to a selected output responsive to a control signal, wherein the selected output is a first output in a first state, and wherein the selected output is a second output in a second state;
- a capacitance circuit comprising a first capacitor electrically coupled to the first output of the select circuit and a second capacitor electrically coupled to the second output of the select circuit, the first capacitor and the second capacitor having different capacitances;
- and
- mixers comprising a first mixer and a second mixer, the first mixer having an input electrically connected to first output of the select circuit by way of the first capacitor, and the second mixer having an input electrically coupled to the second output of the select circuit by way of second capacitor.
4 more elements
An electronic system comprising:
- mixers comprising a first mixer and a second mixer;
- a low-noise transconductance amplifier comprising split cascode current paths, wherein the low-noise transconductance amplifier is configured to provide a radio frequency (RF) output current to the first mixer by way of a first coupling capacitor in a first state of the electronic system, wherein the low-noise transconductance amplifier is configured to provide the RF output current to the second mixer by way of a second coupling capacitor in a second state of the electronic system, wherein the electronic system is configured to operate in the first state and the second state at different times, and wherein the first capacitor and the second capacitor have different capacitances;
- and
- an oscillator routing block comprising a first path between an oscillator and the first mixer and a second path between the oscillator and the second mixer, the oscillator routing block configured to receive an oscillator signal from the oscillator, enable the first path in the first state of the electronic system, and enable the second path in the second state of the electronic system.
1 more element
Dependencies are inferred from the claim text.