The disclosure relates to a phase shifter having a first mode of operation and a second mode of operation, the phase shifter comprising a mixer stage configured to mix an oscillator signal with an analogue signal to provide a phase shifted signal, switching circuitry and a controller arranged to provide the analogue signal to the mixer stage as a voltage in the first mode of operation and as a current in the second mode of operation.

A combined radio frequency (RF) digital-to-analog converter (DAC) may include an in-phase and quadrature-(IQ-) based DAC to generate a phase component of an output RF signal and a polar-based DAC to generate an amplitude component of the RF signal. Additionally, modulation circuitry may combine the amplitude component and the phase component to generate the output RF signal.

Methods and apparatus for sharing digital-to-analog (DAC) converters in a reconfigurable DAC circuit to support two or more transmit chains of a wireless transmitter configured for different radio access technologies (RATs) and/or different transmitter architectures. One example DAC circuit generally includes at least four DACs and a plurality of switches coupled to outputs of the at least four DACs such that the DAC circuit is configured as a multi-channel DAC circuit with at least four channels for a first set of one or more frequency bands and as an interleaved DAC circuit with at least two channels for a second set of one or more frequency bands different from the first set of frequency bands.

A combined radio frequency (RF) digital-to-analog converter (DAC) may include an in-phase and quadrature-(IQ-) based DAC to generate a phase component of an output RF signal and a polar-based DAC to generate an amplitude component of the RF signal. Additionally, modulation circuitry may combine the amplitude component and the phase component to generate the output RF signal.