Abstract: An electronic device may include wireless circuitry having a mixer configured to receive an oscillating signal from oscillator circuitry. The oscillator circuitry can include a chain of buffer circuits referred to as oscillator driver circuitry. Transformers may be coupled at the input and output of each buffer circuit in the chain. Adjustable biasing circuits may be coupled at the input of a selected buffer circuit in the chain. The adjustable biasing circuits can be digital-to-analog converters (DACs) configured to apply a differential direct current (DC) offset voltage to the input of the selected buffer circuit. The differential DC offset voltage can have a value that minimizes a second harmonic component of the oscillator driver circuitry.

Abstract: An electronic device may include wireless circuitry having a radio-frequency mixer. The mixer may include an input stage, an output stage, and a transformer coupled between the input and output stages. The input stage may include input transistors forming a transconductance cell. The output stage may include two pairs of mixer transistors configured to receive an oscillating signal. The transformer may include a primary coil coupled between the input transistors and a secondary coil coupled between the two pairs of mixer transistors. A harmonic rejection circuit may be coupled to a center tap of the secondary coil. The harmonic rejection circuit may be configured to mitigate harmonic signals that are associated with the oscillating signal and that are generated at the inputs of the output stage. The harmonic rejection circuit may include an inductor, an optional capacitor, an optional current source transistor, or other passive component.

Abstract: This disclosure is directed to a Voltage-Controlled Oscillator (VCO) with reduced phase noise compared to other VCOs. The VCO may include a first cell and a second cell separated by common-mode (CM) isolation circuitry. The first cell and the second cell may each include a portion of the CM noise of the VCO. Moreover, gate terminals of switches of the first cell and the second cell may be cross-coupled to drain terminals of the switches of the second cell and the first cell respectively. An interdependency of voltages of the first cell and the second cell may reduce an amplitude of the respective portions of the CM noise on the first cell and the second cell.

Abstract: An electronic device may include wireless circuitry having an oscillator. The oscillator can include a pair of n-type transistors coupled to a first tail node, a pair of p-type transistors coupled to a second tail node, a load inductor coupled between the pair of n-type transistors and the pair of p-type transistors, a load capacitor coupled between the pair of n-type transistors and the pair of p-type transistors, a tunable capacitor, and a first transformer coupled between the first tail node and the tunable capacitor. The oscillator can further include a second transformer coupled between the second tail node and the tunable capacitor. The tunable capacitor can include multiple differential switchable capacitor circuits.

Abstract: Mixer circuitry can include a first mixer transistor configured to receive a first oscillating signal, a second mixer transistor configured to receive a second oscillating signal, and a harmonic conversion gain rejection filter coupled between a source terminal of the first mixer transistor and a source terminal of the second mixer transistor. The harmonic conversion gain rejection filter can be configured to reject a harmonic conversion gain of the mixer circuitry. The mixer circuitry can further include a third mixer transistor configured to receive the first oscillating signal, a fourth mixer transistor configured to receive the second oscillating signal, and another harmonic conversion gain rejection filter coupled between a source terminal of the third mixer transistor and a source terminal of the fourth mixer transistor. The mixer circuitry can further include an output transformer and a notch filter interposed between coils of the output transformer.

Abstract: An electronic device may include wireless circuitry having an oscillator. The oscillator can include a pair of n-type transistors coupled to a first tail node, a pair of p-type transistors coupled to a second tail node, a load inductor coupled between the pair of n-type transistors and the pair of p-type transistors, a load capacitor coupled between the pair of n-type transistors and the pair of p-type transistors, a tunable capacitor, and a first transformer coupled between the first tail node and the tunable capacitor. The oscillator can further include a second transformer coupled between the second tail node and the tunable capacitor. The tunable capacitor can include multiple differential switchable capacitor circuits.

Abstract: An electronic device may include wireless circuitry having an oscillator. The oscillator can include a first transistor having a source-drain terminal coupled to a tail node, a second transistor having a source-drain terminal coupled to the tail node, a first coil having a first terminal coupled to the tail node and having a second terminal coupled to a power supply line, and a second coil inductively coupled to the first coil. The first and second coils can be part of a balun. The balun can be coupled to a tunable capacitance. The tunable capacitance can include multiple differential switchable capacitor circuits. The balun and the tunable capacitance can form a balun phase noise filter configured to reduce a phase noise associated with the oscillator.

Abstract: An electronic device may include wireless circuitry having one or more differential circuits. A differential circuit can include first and second input transistors, first and second degeneration components, and first and second distortion cancellation transistors cross-coupled with the first and second input transistors. The first distortion cancellation transistor can be configured to sense a voltage at the first input transistor and to produce corresponding currents for cancelling a differential mode harmonic distortion current flowing through the second input transistor and for cancelling a common mode harmonic distortion current flowing through the first input transistor.

Abstract: Mixer circuitry can include a first pair of transistors coupled to a first tail node and configured to receive a local oscillator signal, a second pair of transistors coupled to a second tail node and configured to receive the local oscillator signal, a first digital-to-analog converter, a second DAC coupled between the first DAC and of the first pair of transistors, and a third DAC coupled between the first DAC and the second pair of transistors. During a first phase, control circuitry can sweep the first DAC to trim a first and/or other odd order local oscillator feedthrough. During a second phase, the control circuitry can sweep the second DAC to trim a second and/or other even order local oscillator feedthrough. During a third phase, the control circuitry can sweep the second and third DACs to reject signals associated with a second harmonic conversion gain of the mixer circuitry.

Abstract: An electronic device may include wireless circuitry. The wireless circuitry can include first and second input transistors, a third transistor having a gate terminal coupled to a gate terminal of the first input transistor and having a drain terminal coupled to the second input transistor, a fourth transistor having a gate terminal coupled to a gate terminal of the second input transistor and having a drain terminal coupled to the first input transistor, one or more tail circuits coupled to source terminals of the third and fourth transistors, and a bias circuit configured to output a bias voltage that is conveyed to the gate terminals of the first and second input transistors and to the one or more tail circuits. The bias circuit can be coupled to the input transistors via a coil and to the one or more tail circuits via a feedforward path.

Abstract: An electronic device may include wireless circuitry having an oscillator. The oscillator can include a first transistor having a source-drain terminal coupled to a tail node, a second transistor having a source-drain terminal coupled to the tail node, a first coil having a first terminal coupled to the tail node and having a second terminal coupled to a power supply line, and a second coil inductively coupled to the first coil. The first and second coils can be part of a balun. The balun can be coupled to a tunable capacitance. The tunable capacitance can include multiple differential switchable capacitor circuits. The balun and the tunable capacitance can form a balun phase noise filter configured to reduce a phase noise associated with the oscillator.

Abstract: An electronic device may include wireless circuitry having an oscillator. The oscillator can include a pair of n-type transistors coupled to a first tail node, a pair of p-type transistors coupled to a second tail node, a load inductor coupled between the pair of n-type transistors and the pair of p-type transistors, a load capacitor coupled between the pair of n-type transistors and the pair of p-type transistors, a tunable capacitor, and a first transformer coupled between the first tail node and the tunable capacitor. The oscillator can further include a second transformer coupled between the second tail node and the tunable capacitor. The tunable capacitor can include multiple differential switchable capacitor circuits.

Abstract: This disclosure is directed to a Voltage-Controlled Oscillator (VCO) with improved phase noise compared to other VCOs. The VCO may include a first cell and a second cell separated by common-mode (CM) isolation circuitry to reduce an amplitude of CM noise at an output signal. The CM isolation circuitry may inductively couple the first cell to the second cell for generating the output signal based on a resonant frequency range including resonant frequencies of the CM isolation circuitry, the first cell, and the second cell. As such, the first cell and the second cell may each include a portion of an entirety of the CM noise. In some cases, the portions of the CM noise on the first cell and/or the second cell may improve a signal to noise ratio of the output signal.

Abstract: Mixer circuitry can include a first pair of transistors coupled to a first tail node and configured to receive a local oscillator signal, a second pair of transistors coupled to a second tail node and configured to receive the local oscillator signal, a first digital-to-analog converter, a second DAC coupled between the first DAC and of the first pair of transistors, and a third DAC coupled between the first DAC and the second pair of transistors. During a first phase, control circuitry can sweep the first DAC to trim a first and/or other odd order local oscillator feedthrough. During a second phase, the control circuitry can sweep the second DAC to trim a second and/or other even order local oscillator feedthrough. During a third phase, the control circuitry can sweep the second and third DACs to reject signals associated with a second harmonic conversion gain of the mixer circuitry.

Abstract: This disclosure is directed to a Voltage-Controlled Oscillator (VCO) with reduced phase noise compared to other VCOs. The VCO may include a first cell and a second cell separated by common-mode (CM) isolation circuitry. The first cell and the second cell may each include a portion of the CM noise of the VCO. Moreover, gate terminals of switches of the first cell and the second cell may be cross-coupled to drain terminals of the switches of the second cell and the first cell respectively. An interdependency of voltages of the first cell and the second cell may reduce an amplitude of the respective portions of the CM noise on the first cell and the second cell.

Abstract: This disclosure is directed to a Voltage-Controlled Oscillator (VCO) with improved phase noise compared to other VCOs. The VCO may include a first cell and a second cell separated by common-mode (CM) isolation circuitry to reduce an amplitude of CM noise at an output signal. The CM isolation circuitry may inductively couple the first cell to the second cell for generating the output signal based on a resonant frequency range including resonant frequencies of the CM isolation circuitry, the first cell, and the second cell. As such, the first cell and the second cell may each include a portion of an entirety of the CM noise. In some cases, the portions of the CM noise on the first cell and/or the second cell may improve a signal to noise ratio of the output signal.

Abstract: This disclosure is directed to a Voltage-Controlled Oscillator (VCO) with improved phase noise compared to other VCOs. The VCO may include a first cell and a second cell separated by common-mode (CM) isolation circuitry to reduce an amplitude of CM noise at an output signal. The CM isolation circuitry may inductively couple the first cell to the second cell for generating the output signal based on a resonant frequency range including resonant frequencies of the CM isolation circuitry, the first cell, and the second cell. As such, the first cell and the second cell may each include a portion of an entirety of the CM noise. In some cases, the portions of the CM noise on the first cell and/or the second cell may improve a signal to noise ratio of the output signal.

Abstract: An electronic device may include wireless circuitry having a mixer configured to receive an oscillating signal from oscillator circuitry. The oscillator circuitry can include a chain of buffer circuits sometimes referred to as oscillator driver circuitry. Transformers may be coupled at the input and output of each buffer circuit in the chain. Adjustable biasing circuits may be formed at the input of a selected buffer circuit in the chain of the buffer circuits. The adjustable biasing circuits can be digital-to-analog converters (DACs). The adjustable biasing circuits may be configured to apply a differential direct current (DC) offset voltage to the input of the selected buffer circuit. The differential DC offset voltage can have a value chosen to minimize a second harmonic component of the oscillator driver circuitry. Configured and operated in this way, a second harmonic conversion gain of the mixer can be reduced and can improve the transmit and receive performance of the wireless circuitry.

Abstract: An electronic device may include wireless circuitry having one or more differential circuits. A differential circuit can include first and second input transistors, first and second degeneration components, and first and second distortion cancellation transistors cross-coupled with the first and second input transistors. The first distortion cancellation transistor can be configured to sense a voltage at the first input transistor and to produce corresponding currents for cancelling a differential mode harmonic distortion current flowing through the second input transistor and for cancelling a common mode harmonic distortion current flowing through the first input transistor.

Abstract: An electronic device may include wireless circuitry having a mixer configured to receive an oscillating signal from oscillator circuitry. The oscillator circuitry can include a chain of buffer circuits sometimes referred to as oscillator driver circuitry. Transformers may be coupled at the input and output of each buffer circuit in the chain. Adjustable biasing circuits may be formed at the input of a selected buffer circuit in the chain of the buffer circuits. The adjustable biasing circuits can be digital-to-analog converters (DACs). The adjustable biasing circuits may be configured to apply a differential direct current (DC) offset voltage to the input of the selected buffer circuit. The differential DC offset voltage can have a value chosen to minimize a second harmonic component of the oscillator driver circuitry. Configured and operated in this way, a second harmonic conversion gain of the mixer can be reduced and can improve the transmit and receive performance of the wireless circuitry.