Abstract: Techniques for designing baseband processing circuitry for radio IC's. In an aspect, techniques for differential-to-single-ended conversion in a baseband portion of the IC are disclosed to reduce the pin count and package size for RF IC's. In another aspect, the converter includes selectable narrowband and wideband amplifiers, wherein the wideband amplifiers may be implemented using transistor devices having smaller area than corresponding transistor devices of narrowband amplifiers. Further techniques for bypassing one or more elements, and for implementing a low-pass filter of the converter using an R-C filter network, are described.

Abstract: Amplifiers with inductive degeneration and configurable gain and input matching are disclosed. In an exemplary design, an apparatus includes a gain transistor, an inductor, and an input matching circuit for an amplifier. The gain transistor has a variable gain determined based on its bias current. The inductor is coupled between the gain transistor and circuit ground. The input matching circuit is selectively coupled to the gain transistor based on the variable gain of the gain transistor. For example, the input matching circuit may be coupled to the gain transistor in a low-gain mode and decoupled from the gain transistor in the high-gain mode. In an exemplary design, the input matching circuit includes a resistor, a capacitor, and a second transistor coupled in series. The resistor is used for input matching of the amplifier. The second transistor couples or decouples the resistor to or from the gain transistor.

Abstract: A device includes a first and a second low noise amplifier (LNA), a first degenerative inductance coupled between the first LNA and ground by a first ground connection, and a second degenerative inductance coupled between the second LNA and ground by a second ground connection, the first and second degenerative inductances configured to establish negative inductive coupling between the first and second degenerative inductances.

Abstract: A device includes a first amplifier circuit coupled to a first transformer and a second transformer, the first transformer selectively coupled to a first shared power distribution network through a first switch, the second transformer selectively coupled to a second shared power distribution network through a second switch.

Abstract: Multi-output amplifiers with configurable source degeneration inductance and having good performance are disclosed. In an exemplary design, an apparatus (e.g., a wireless device or an integrated circuit) includes a gain transistor and a configurable degeneration inductor for an amplifier. The gain transistor receives an input signal and provides an amplified signal. The amplifier provides a single output signal in a first operating mode or a plurality of output signals in a second operating mode. The configurable degeneration inductor is coupled to the gain transistor and provides a first source degeneration inductance in the first operating mode or a second source degeneration inductance in the second operating mode. The second source degeneration inductance is less than the first source degeneration inductance and may be dependent on the number of output signals generated in the second operating mode.

Abstract: Split amplifiers with configurable gain and linearization circuitry are disclosed. In an exemplary design, an apparatus includes first and second amplifier circuits and a linearization circuit, which may be part of an amplifier. The first and second amplifier circuits are coupled in parallel and to an amplifier input. The linearization circuit is also coupled to the amplifier input. The first and second amplifier circuits are enabled in a high-gain mode. One of the first and second amplifier circuits is enabled in a low-gain mode. The linearization circuit is enabled in the second mode and disabled in the first mode. The amplifier is split into multiple sections. Each section includes an amplifier circuit and is a fraction of the amplifier. High linearly may be obtained using one amplifier circuit and the linearization circuit in the low-gain mode.

Abstract: Techniques for designing baseband processing circuitry for radio IC's. In an aspect, techniques for differential-to-single-ended conversion in a baseband portion of the IC are disclosed to reduce the pin count and package size for RF IC's. In another aspect, the converter includes selectable narrowband and wideband amplifiers, wherein the wideband amplifiers may be implemented using transistor devices having smaller area than corresponding transistor devices of narrowband amplifiers. Further techniques for bypassing one or more elements, and for implementing a low-pass filter of the converter using an R-C filter network, are described.

Abstract: Techniques for improving electro-static discharge (ESD) performance in integrated circuits (IC's). In an aspect, one or more protective diodes are provided between various nodes of the IC. For example, protective diode(s) may be provided between the drain and gate of an amplifier input transistor, and/or between the drain and ground, etc. In certain exemplary embodiments, the amplifier may be a cascode amplifier. Further aspects for effectively dealing with ESD phenomena are described.

Abstract: Amplifiers with configurable mutually-coupled source degeneration inductors are disclosed. In an exemplary design, an apparatus (e.g., a wireless device or an integrated circuit) includes a gain transistor and a plurality of inductors, which may implement an amplifier. The gain transistor receives an input signal and provides an amplified signal. The plurality of inductors are mutually coupled, are coupled to the gain transistor, and provide a programmable source degeneration inductance for the gain transistor. The inductors may have a positive coupling coefficient and may provide a larger source degeneration inductance. Alternatively, the inductors may have a negative coupling coefficient and may provide a smaller source degeneration inductance.

Abstract: Amplifiers with multiple outputs and separate gain control per output are disclosed. In an exemplary design, an apparatus (e.g., a wireless device or an integrated circuit) may include first and second amplifier circuits. The first amplifier circuit may receive and amplify an input radio frequency (RF) signal based on a first variable gain and provide a first amplified RF signal. The second amplifier circuit may receive and amplify the input RF signal based on a second variable gain and provide a second amplified RF signal. The input RF signal may include a plurality of transmitted signals being received by the wireless device. The first variable gain may be adjustable independently of the second variable gain. Each variable gain may be set based on the received power level of at least one transmitted signal being received by the wireless device.

Abstract: Techniques for providing a receiver front end supporting carrier aggregation with gain alignment and improved matching across modes. In an aspect, auxiliary circuitry is configurable to selectively enable or disable mutual coupling between a source degeneration inductor of an LNA input transistor and an auxiliary inductor. A negative turns ratio coupling is provided between the inductors, such that the effective inductance of the source degeneration inductor is lowered when mutually coupled to the auxiliary inductor. In a non-carrier aggregation (non-CA) mode, the auxiliary inductor is disabled, while in a carrier aggregation (CA) mode, the auxiliary inductor is enabled. In this manner, using a single transistor, gain alignment across non-CA and CA modes is achieved. Furthermore, matching is preserved across non-CA and CA modes using a single external matching component.

Abstract: Techniques for providing low-cost and effective jammer rejection for a radio receiver. In an aspect, a notch filter is provided between a transformer and a differential mixer in the receiver. The notch frequency of the notch filter may be selected to correspond to an expected jammer frequency to effectively attenuate the jammer signal prior to down-conversion mixing by the mixer. The notch filter may be implemented using various techniques, e.g., an L-C combination having adjustable capacitance, and/or elliptic or Chebyshev filters.

Abstract: Amplifiers with boosted or deboosted source degeneration inductance are disclosed. In an exemplary design, an apparatus includes an amplifier circuit and a feedback circuit. The amplifier circuit receives an input signal and provides an output signal and includes a source degeneration inductor. The feedback circuit is coupled between a node of the amplifier circuit and the source degeneration inductor. The feedback circuit provides feedback to vary an input impedance of an amplifier including the amplifier circuit and the feedback circuit. The feedback circuit may be programmable and may be enabled to provide feedback or disabled to provide no feedback. Alternatively, the feedback circuit may always be enabled to provide feedback. In either case, the feedback circuit may have a variable gain to provide a variable input impedance for the amplifier.

Abstract: Techniques for routing and shielding signal lines to improve isolation between the signal lines are disclosed. In an exemplary design, an apparatus includes first, second, and third signal lines and a switch. The first, second, and third signal lines are configurable to carry first, second, and third signals, respectively. The switch is coupled between the second signal line and AC ground and is closed when the second signal line is not carrying the second signal. The second signal line isolates the first and third signal lines when the switch is closed. Adjacent signal lines are not active at the same time. A signal line may include positive and negative signal lines, which may have at least one cross over in order to cancel coupling between the positive and negative signal lines.

Abstract: Split amplifiers with configurable gain and linearization circuitry are disclosed. In an exemplary design, an apparatus includes first and second amplifier circuits and a linearization circuit, which may be part of an amplifier. The first and second amplifier circuits are coupled in parallel and to an amplifier input. The linearization circuit is also coupled to the amplifier input. The first and second amplifier circuits are enabled in a high-gain mode. One of the first and second amplifier circuits is enabled in a low-gain mode. The linearization circuit is enabled in the second mode and disabled in the first mode. The amplifier is split into multiple sections. Each section includes an amplifier circuit and is a fraction of the amplifier. High linearly may be obtained using one amplifier circuit and the linearization circuit in the low-gain mode.

Abstract: Amplifiers with inductive degeneration and configurable gain and input matching are disclosed. In an exemplary design, an apparatus includes a gain transistor, an inductor, and an input matching circuit for an amplifier. The gain transistor has a variable gain determined based on its bias current. The inductor is coupled between the gain transistor and circuit ground. The input matching circuit is selectively coupled to the gain transistor based on the variable gain of the gain transistor. For example, the input matching circuit may be coupled to the gain transistor in a low-gain mode and decoupled from the gain transistor in the high-gain mode. In an exemplary design, the input matching circuit includes a resistor, a capacitor, and a second transistor coupled in series. The resistor is used for input matching of the amplifier. The second transistor couples or decouples the resistor to or from the gain transistor.

Abstract: Multi-output amplifiers with configurable source degeneration inductance and having good performance are disclosed. In an exemplary design, an apparatus (e.g., a wireless device or an integrated circuit) includes a gain transistor and a configurable degeneration inductor for an amplifier. The gain transistor receives an input signal and provides an amplified signal. The amplifier provides a single output signal in a first operating mode or a plurality of output signals in a second operating mode. The configurable degeneration inductor is coupled to the gain transistor and provides a first source degeneration inductance in the first operating mode or a second source degeneration inductance in the second operating mode. The second source degeneration inductance is less than the first source degeneration inductance and may be dependent on the number of output signals generated in the second operating mode.

Abstract: Amplifiers with multiple outputs and separate gain control per output are disclosed. In an exemplary design, an apparatus (e.g., a wireless device or an integrated circuit) may include first and second amplifier circuits. The first amplifier circuit may receive and amplify an input radio frequency (RF) signal based on a first variable gain and provide a first amplified RF signal. The second amplifier circuit may receive and amplify the input RF signal based on a second variable gain and provide a second amplified RF signal. The input RF signal may include a plurality of transmitted signals being received by the wireless device. The first variable gain may be adjustable independently of the second variable gain. Each variable gain may be set based on the received power level of at least one transmitted signal being received by the wireless device.

Abstract: Techniques for calibrating a receiver based on a local oscillator (LO) signal from another receiver are disclosed. In an exemplary design, an apparatus (e.g., a wireless device or an integrated circuit) includes first and second local oscillator (LO) generators. The first LO generator generates a first LO signal used by a first receiver for frequency downconversion. The second LO generator generates a second LO signal used by a second receiver for frequency downconversion in a first operating mode. The second LO signal is used to generate a test signal for the first receiver in a second operating mode. The second LO signal may be provided as the test signal or may be amplitude modulated with a modulating signal to generate the test signal. The test signal may be used to calibrate residual sideband (RSB), second order input intercept point (IIP2), receive path gain, etc.

Abstract: Amplifiers with noise splitting to improve noise figure are disclosed. In an exemplary design, an apparatus (e.g., a wireless device, an integrated circuit, etc.) includes a plurality of amplifier circuits and at least one interconnection circuit. The amplifier circuits receive an input radio frequency (RF) signal. The interconnection circuit(s) are coupled between the plurality of amplifier circuits. Each interconnection circuit is closed to short the outputs or internal nodes of two amplifier circuits coupled to that interconnection circuit. The plurality of amplifier circuits may include a plurality of gain circuits coupled to a plurality of current buffers, one gain circuit and one current buffer for each amplifier circuit. Each amplifier circuit provides an output current, which may include a portion of the current from each of the plurality of gain circuits when the plurality of amplifier circuits are enabled.