Abstract:
Aspects of a method and system for a transformer-based high performance cross-coupled low noise amplifier may include one or more circuits that integrate within a single chip, a balun with a low-noise amplifier. A DC current biasing path for the low-noise amplifier may be provided through the integrated balun. The low-noise amplifier may be configured as a cross-coupled low-noise amplifier, where the balun may be directly coupled to the cross-coupled low-noise amplifier. The balun may comprise two or more inductors, wherein one or more of the inductors may provide an electrical path for allowing a DC bias current to flow to ground. Integrating a balun on a single chip with a low-noise amplifier may allow the use of a single received signal input terminal. The biasing voltage may be selected to optimize performance of the low-noise amplifier.
Abstract:
Aspects of a method and system for processing signals in a high performance receive chain may include amplifying radio frequency signals in amplifier chains in a multistandard radio frequency front-end, comprising one or more shared processing stages, and combining, with substantially equal gain, a number of phase-shifted radio frequency signals of the radio frequency signals into substantially equal-gain-combined radio frequency signals. The substantially equal-gain-combined radio frequency signals may be demodulated to obtain inphase channels and quadrature channels. A number of inphase channels and quadrature channels may be processed in I-channel processing blocks and Q-channel processing blocks to generate an output analog baseband signal. The multistandard radio frequency front-end may be capable of processing Bluetooth® signals and Wireless Local Area Network (WLAN) signals. The amplifier chains may comprise a first amplifier and a second amplifier, where the first amplifier may be shared between Bluetooth® signal processing paths and WLAN signal processing paths.
Abstract:
Fully integrated compact cross-coupled low noise amplifier. A circuitry implementation that includes two pairs of metal oxide semiconductor field-effect transistors (MOSFETs) (either N-type of P-type) operates as an LNA, which can be used within any of a wide variety of communication devices. A majority of the elements are integrated within the design and need not be implemented off-chip, and this can provide for a reduction in area required by the circuitry. A differential 100Ω input impedance is provided by this design. A higher than typical power supply voltage can be employed (if desired) to accommodate one possible implementation that includes two parallel implemented resistors to ground.
Abstract:
Methods and systems are provided to calibrate an oscillator circuit to reduce frequency pulling as a result of a change in power to a portion of the oscillator circuit. In an embodiment, an oscillator is coupled to a clock buffer circuit and a tuning capacitor configured to tune a frequency of the oscillator to a baseline frequency required for cellular communications. A change in power to the clock buffer circuit initiates a change in an amount of capacitance seen by the oscillator, which negatively impacts the tuning of the oscillator. A register stores a frequency offset caused by the change in power, and the tuning capacitor is adjusted, using the frequency offset, in response to the change in power, such that the total amount of capacitance seen by the oscillator is not changed when the change in power occurs.
Abstract:
Aspects of a method and system for a transformer-based high performance cross-coupled low noise amplifier may include one or more circuits that integrate within a single chip, a balun with a low-noise amplifier. A DC current biasing path for the low-noise amplifier may be provided through the integrated balun. The low-noise amplifier may be configured as a cross-coupled low-noise amplifier, where the balun may be directly coupled to the cross-coupled low-noise amplifier. The balun may comprise two or more inductors, wherein one or more of the inductors may provide an electrical path for allowing a DC bias current to flow to ground. Integrating a balun on a single chip with a low-noise amplifier may allow the use of a single received signal input terminal. The biasing voltage may be selected to optimize performance of the low-noise amplifier.
Abstract:
A method to provide a low-power clock signal or a low-noise clock signal is described herein. It is determined whether a low-power mode or a low-noise mode is in use. A voltage reference input of a low-dropout voltage regulator (LDO) is switched to a low-power voltage reference for low-power mode and to a low-noise voltage reference for low-noise mode. The LDO provides a constant voltage output to a crystal oscillator. A clock signal is generated using the crystal oscillator. The clock signal is limited using a low-power limiter to generate a low-power output clock signal and/or is limited using a low-noise limiter to generate a low-noise clock signal. The low-power output clock signal or the low-noise output clock signal is selected using a mux.
Abstract:
A frequency tuning device for use in a crystal oscillator circuit includes a first fine tuning array of capacitors, a second fine tuning array of capacitors and a coarse tuning array of capacitors coupled in parallel to produce a tuning capacitance for tuning the crystal oscillator. The first fine tuning array of capacitors includes a binary weighted switched capacitor network, the second fine tuning array of capacitors includes a thermometer coded switched capacitor network and the coarse tuning array of capacitors includes a binary weighted switched capacitor network with a different unit capacitance value than the first and second fine tuning arrays.
Abstract:
A differential crystal oscillator circuit uses a bias transistor to generate a bias voltage from a bias current. The bias voltage is supplied to the control terminals of a differential pair of transistors. The differential transistors operate to produce a differential output between corresponding end terminals thereof, which is provided to a reference crystal oscillator to establish an oscillation frequency at the differential output.
Abstract:
A differential crystal oscillator circuit uses a bias transistor to generate a bias voltage from a bias current. The bias voltage is supplied to the control terminals of a differential pair of transistors. The differential transistors operate to produce a differential output between corresponding end terminals thereof, which is provided to a reference crystal oscillator to establish an oscillation frequency at the differential output.
Abstract:
Cross-coupled low noise amplifier for cellular applications. A circuitry implementation that includes two pairs of metal oxide semiconductor field-effect transistors (MOSFETs) (either N-type of P-type) operates as an LNA, which can be used within any of a wide variety of communication devices. In one embodiment, this design is particularly adaptable to cellular telephone applications. A majority of the elements are integrated within the design and need not be implemented off-chip, and this can provide for a reduction in area required by the circuitry. A very high output impedance is provided by using two transistors (implemented in a triple well configuration) with resistive source degeneration. A higher than typical power supply voltage can be employed (if desired) to accommodate the voltage drops of the resistors and transistors.