Abstract: Methods and devices for enhancing performance of a power splitter are presented. According to one aspect, the power splitter is realized via lumped elements that include inductively coupled coils. Values of the lumped elements are based on an equivalent circuit of the power splitter that includes a star topology provided by a mutual inductance connected to a first port of the power splitter and respective inductances of the inductively coupled coils modified by the mutual inductance connected between the mutual inductance and respective second and third ports of the power splitter. A coupling factor of the inductively coupled coils has a magnitude that is in a range from 0.15 to 0.45. The coupling factor is negative. Respective capacitors are connected to the ports of the power splitter. The respective capacitors include switchable capacitors.

Abstract: A receiver topology for supporting various combinations of interband carrier aggregation (CA) signals, intraband non-contiguous CA and non-CA signals having different combinations of signals aggregated therein.

Abstract: Methods and devices addressing design of wideband LNAs with gain modes are disclosed. The disclosed teachings can be used to reconfigure RF receiver front-end to operate in various applications imposing stringent and conflicting requirements. Wideband and narrowband input and output matching with gain modes using a combination of the same hardware and a switching network are also disclosed. The described methods and devices also address carrier aggregation requirements and provide solutions that can be used both in single-mode and split-mode operations.

Abstract: A flexible multi-path RF adaptive tuning network switch architecture that counteracts impedance mismatch conditions arising from various combinations of coupled RF band filters, particularly in a Carrier Aggregation-based (CA) radio system. In one version, a digitally-controlled tunable matching network is coupled to a multi-path RF switch in order to provide adaptive impedance matching for various combinations of RF band filters. Optionally, some or all RF band filters include an associated digitally-controlled filter pre-match network to further improve impedance matching. In a second version, some or all RF band filters coupled to a multi-path RF switch include a digitally-controlled phase matching network to provide necessary per-band impedance matching. Optionally, a digitally-controlled tunable matching network may be included on the common port of the multi-path RF switch to provide additional impedance matching capability.

Abstract: An amplifier circuit configuration capable of processing non-contiguous intra-band carrier aggregate (CA) signals using amplifiers is disclosed herein. In some cases, each of a plurality of amplifiers is an amplifier configured as a cascode (i.e., a two-stage amplifier having two transistors, the first configured as a “common source” input transistor, e.g., input field effect transistor (FET), and the second configured in a “common gate” configuration as a cascode output transistor, (e.g. cascode output FET). In other embodiments, the amplifier may have additional transistors (i.e., more than two stages and/or stacked transistors). The amplifier circuit configuration can be operated in either single mode or split mode. A switchable coupling is placed between the drain of the input FETs of each amplifier within the amplifier circuit configuration.

Abstract: A receiver front end having low noise amplifiers (LNAs) is disclosed herein. A cascode having a “common source” configured input FET and a “common gate” configured output FET can be turned on or off using the gate of the output FET. A first switch is provided that allows a connection to be either established or broken between the source terminal of the input FET of each LNA. A drain switch is provided between the drain terminals of input FETs to place the input FETs in parallel. This increases the gm of the input stage of the amplifier, thus improving the noise figure of the amplifier.

Abstract: Methods and devices for realizing RF processing paths associated to different frequency bands are presented. According to one aspect, the RF processing paths are provided by a hybrid input LNA RF frontend that includes RF processing paths that are dedicated to specific frequency bands and RF processing paths that are shared between several frequency bands. Sharing of the RF processing paths is provided by an input combiner network and/or a multi-input cascode amplifier that includes a cascode transistor that is coupled to at least two input transistors. Further presented in a toolkit that includes circuit blocks that can be used in specific combinations to customize the RF processing paths to achieve specific performance or cost optimization. A decision tree based on performance and cost priorities assigned to each of the frequency bands is used to provide the specific combinations.

Abstract: A receiver topology for supporting various combinations of interband carrier aggregation (CA) signals, intraband non-contiguous CA and non-CA signals having different combinations of signals aggregated therein.

Abstract: Methods and devices for reducing DC current consumption of a multi-stage LNA amplifier. According to one aspect, first and second amplification stages are stacked to provide a common conduction path of a DC current. The first stage includes a common-source amplifier, the second stage includes a common-drain amplifier. Coupling between the two stages is provided by series connection of load inductors of the respective stages and a capacitor coupled at a common node between the inductors. According to another aspect, a current splitter circuit is used to split a current to the first stage according to two separate conduction paths, one common path to the two stages, and another separate from the second stage. According to yet another aspect, the current splitter circuit includes a feedback loop that controls the splitting of the current so to maintain a constant current through the common path.

Abstract: Methods and devices addressing design of wideband LNAs with gain modes are disclosed. The disclosed teachings can be used to reconfigure RF receiver front-end to operate in various applications imposing stringent and conflicting requirements. Wideband and narrowband input and output matching with gain modes using a combination of the same hardware and a switching network are also disclosed. The described methods and devices also address carrier aggregation requirements and provide solutions that can be used both in single-mode and split-mode operations.

Abstract: Methods and devices to mitigate the detrimental effects of highly capacitive output routes of multiple gain low noise amplifiers on the overall performance of the circuit are disclosed. The disclosed methods and devices implement the same inductive element across the output load in both the low gain and high gain operational modes. Furthermore, such devices implement switches to control the selection of different signal paths for the high gain and low gain mode. The implemented switches are also used to selectively adjust the isolation of the output stage of the LNA.

Abstract: A low noise amplifier (LNA) with configurable feedback that includes a filter circuit for improved stability is presented. The filter circuit includes an L-C tank. The filter circuit further includes a resistor in parallel with the L-C tank. The filter circuit is tunable/adjustable/programmable. The filter circuit further includes a capacitor selectively arranged in parallel with the L-C tank. The filter circuit is coupled to an input of the LNA via a series resistor. The filter circuit is coupled between the input and an output of the LNA via one or more switches. The LNA includes a first stage with a common-source transistor and a common-gate transistor. The LNA further includes a wideband feedback circuit coupled between the input and output of the first stage. The LNA includes a source-follower circuit. The source follower circuit is configurable as a second stage, or a feedback circuit, coupled to the filter circuit.

Abstract: Methods and circuital arrangements for turning OFF branches of a multi-branch cascode amplifier are presented. First and second switching arrangements coupled to a branch allow turning OFF the branch while protecting transistors of the branch from a supply voltage that may be greater than a tolerable voltage of the transistors. The first switching arrangement includes a transistor-based switch that is in series connection with the transistors of the branch. The first switching arrangement drops the supply voltage during the OFF state of the branch and provides a conduction path for a current through the branch during the ON state of the branch. A resistor and a shunting switch are coupled to a gate of the transistor-based switch to reduce parasitic coupling effects of the transistor-based switch upon an RF signal coupled to the branch during the ON state and OFF state of the branch.

Abstract: Low noise amplifier (LNA) architectures addressing the parasitic challenges in the circuit in order to meet the high gain and bandwidth requirement at higher frequencies are disclosed. The described LNAs include cascode transistors and implement a tunable inductor in series with the gate terminal of a transistor of the cascode transistors to improve the gain and bandwidth of the LNAs and achieve high gain wideband switching LNAs.

Abstract: Split low noise amplifier (LNA) architectures providing an improved tradeoff between the noise figure (NF) and the output-to-output isolation are disclosed. The described LNAs include cascode transistors in two amplification paths and an inductive element including a pair of inductors and a common inductor. The inductance values of the inductors and the common inductor can be selected to obtain an improved tradeoff between the NF and isolation while meeting the output matching conditions.

Abstract: Circuits and methods for a multi-gain mode amplifier, particularly an LNA, that achieves wideband output impedance matching and high gain while maintaining low power and a low NF in a highest gain mode, and which can switch to one or more lower gain modes that achieve higher linearity with lower power. In a highest gain mode, an inductor is selectively inserted between the amplified-signal terminal of an amplification core and an output LC output matching network. The inductor, when inserted, provides wideband output impedance matching, functioning as a series peaking inductor; accordingly, the inserted inductor delays current flow to the output capacitor and lowers the rise time of signal changes across the output capacitor. In addition, higher gain can be achieved compared to a conventional LC output impedance matching topology due to a higher impedance at the amplified-signal terminal of the amplification core.

Abstract: A receiver front end amplifier 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” configured input FET and a “common gate” configured output FET can be turned on or off using the gate of the output FET. A first switch is provided that allows a connection to be either established or broken between the source terminal of the input FET of each LNA. Further switches used for switching degeneration inductors, gate capacitors, and gate to ground capacitors for each leg can be used to further improve the matching performance of the invention.

Abstract: Methods and devices for reducing DC current consumption of a multi-stage LNA amplifier. According to one aspect, first and second amplification stages are stacked to provide a common conduction path of a DC current. The first stage includes a common-source amplifier, the second stage includes a common-drain amplifier. Coupling between the two stages is provided by series connection of load inductors of the respective stages and a capacitor coupled at a common node between the inductors. According to another aspect, a current splitter circuit is used to split a current to the first stage according to two separate conduction paths, one common path to the two stages, and another separate from the second stage. According to yet another aspect, the current splitter circuit includes a feedback loop that controls the splitting of the current so to maintain a constant current through the common path.

Abstract: Methods and circuital arrangements for turning OFF branches of a multi-branch cascode amplifier are presented. First and second switching arrangements coupled to a branch allow turning OFF the branch while protecting transistors of the branch from a supply voltage that may be greater than a tolerable voltage of the transistors. The first switching arrangement includes a transistor-based switch that is in series connection with the transistors of the branch. The first switching arrangement drops the supply voltage during the OFF state of the branch and provides a conduction path for a current through the branch during the ON state of the branch. A resistor and a shunting switch are coupled to a gate of the transistor-based switch to reduce parasitic coupling effects of the transistor-based switch upon an RF signal coupled to the branch during the ON state and OFF state of the branch.

Abstract: A front end module (FEM) integrated circuit (IC) architecture that uses the same LNA in each of several frequency bands extending over a wide frequency range. In some embodiments, switched impedance circuits distributed throughout the front end circuit allow selection of the frequency response and impedances that are optimized for particular performance parameters targeted for a desired device characteristic. Such switched impedance circuits tune the output and input impedance match and adjust the gain of the LNA for specific operating frequencies and gain targets. In addition, adjustments to the bias of the LNA can be used to optimize performance trade-offs between the total direct current (DC) power dissipated versus radio frequency (RF) performance. By selecting appropriate impedances throughout the circuit using switched impedance circuits, the LNA can be selectively tuned to operate optimally at a selected bias for operation within selected frequency bands.