LNA with programmable linearity
AssigneepSemi Corporation
InventorsHossein Noori, Chih-Chieh Cheng
Life of this patent
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Abstract
A receiver front end capable of receiving and processing intraband non-contiguous carrier aggregate (CA) signals using multiple low noise amplifiers (LNAs) is disclosed herein. A cascode having a “common source” input stage and a “common gate” output stage can be turned on or off using the gate of the output stage. A first switch is provided that allows a connection to be either established or broken between the source terminal of the input stage of each cascode. Further switches used for switching degeneration inductors, gate/sources caps and gate to ground caps for each legs can be used to further improve the matching performance of the invention.
Claims13
An amplifier comprising:
- (a) a plurality of amplifier branches, at least one of which includes a driver field effect transistor (FET) having a drain, source and gate, and a corresponding cascode FET having a drain, source and gate, the drain of the driver FET coupled to the source of the corresponding cascode FET, the drain of each cascode FET coupled together;
- (b) a plurality of branch control switches, each branch control switch associated with one of the amplifier branches and coupled to the gate of the cascode FET within the corresponding amplifier branch;
- (c) a load inductance having a first and second terminal, the first terminal coupled to the drains of the cascode FETs and the second terminal coupled to a voltage supply;
- (d) an output capacitor having a first and second terminal, the first terminal coupled to the drains of the cascode FETs and the second terminal coupled to an amplifier output;
- (e) a plurality of gain control compensation capacitors, each having a first and second terminal, the first terminal of each gain control compensation capacitor coupled to the drains of the cascode FETs;
- (f) a plurality of gain control compensation switches, each gain control compensation switch corresponding to one of the plurality of gain control compensation capacitors and having a first and second terminal, the first terminal coupled to the second terminal of the corresponding gain control compensation capacitor and the second terminal of each of the gain control compensation switches coupled to the amplifier output to place the corresponding gain control compensation capacitor in parallel with an output capacitor when the corresponding gain control compensation switch is closed.
Dependencies are inferred from the claim text.