Abstract: A transceiver or RF front end employing a transformer with a low loss transmit/receive (T/R) switch circuit in the ground path. In various embodiments, differential outputs of a power amplifier are coupled to the first winding of the transformer, while the input of a low noise amplifier is coupled to the second side of the transformer via a matching inductor. The T/R switch circuit, which may be a thin oxide CMOS transistor, is coupled between the second side of the transformer and ground. In operation, the T/R switch circuit may be enabled during transmit mode operations of the power amplifier, such that a low impedance path to ground is provided at the input of the low noise amplifier, thereby protecting it from high voltage swings generated by the power amplifier.

Abstract: A transceiver or RF front end employing a transformer with a low loss transmit/receive (T/R) switch circuit in the ground path. In various embodiments, differential outputs of a power amplifier are coupled to the first winding of the transformer, while the input of a low noise amplifier is coupled to the second side of the transformer via a matching inductor. The T/R switch circuit, which may be a thin oxide CMOS transistor, is coupled between the second side of the transformer and ground. In operation, the T/R switch circuit may be enabled during transmit mode operations of the power amplifier, such that a low impedance path to ground is provided at the input of the low noise amplifier, thereby protecting it from high voltage swings generated by the power amplifier.

Abstract: A transceiver or RF front end employing a transformer with a low loss transmit/receive (T/R) switch circuit in the ground path. In various embodiments, differential outputs of a power amplifier are coupled to the first winding of the transformer, while the input of a low noise amplifier is coupled to the second side of the transformer via a matching inductor. The T/R switch circuit, which may be a thin oxide CMOS transistor, is coupled between the second side of the transformer and ground. In operation, the T/R switch circuit may be enabled during transmit mode operations of the power amplifier, such that a low impedance path to ground is provided at the input of the low noise amplifier, thereby protecting it from high voltage swings generated by the power amplifier.

Abstract: A transceiver or RF front end employing a transformer with a low loss transmit/receive (T/R) switch circuit in the ground path. In various embodiments, differential outputs of a power amplifier are coupled to the first winding of the transformer, while the input of a low noise amplifier is coupled to the second side of the transformer via a matching inductor. The T/R switch circuit, which may be a thin oxide CMOS transistor, is coupled between the second side of the transformer and ground. In operation, the T/R switch circuit may be enabled during transmit mode operations of the power amplifier, such that a low impedance path to ground is provided at the input of the low noise amplifier, thereby protecting it from high voltage swings generated by the power amplifier.

Abstract: A phase-locked loop circuit includes an array of selectable capacitors formed within the phase-locked loop circuit to enable the phase-locked loop circuit to provide a degree of coarse frequency control by adding or removing capacitors and a degree of fine frequency control by sinking or sourcing current from a charge pump into a loop filter. A finite state machine is provided within a voltage controlled oscillator calibration circuit that communicates with an external baseband processor to initiate a calibration process, and further to determine how many capacitors of an array of capacitors if formed within the phase-locked loop circuit should be coupled to provide the coarse frequency control.

Abstract: A phase-locked loop circuit includes an array of selectable capacitors formed within the phase-locked loop circuit to enable the phase-locked loop circuit to provide a degree of coarse frequency control by adding or removing capacitors and a degree of fine frequency control by sinking or sourcing current from a charge pump into a loop filter. A finite state machine is provided within a voltage controlled oscillator calibration circuit that communicates with an external baseband processor to initiate a calibration process, and further to determine how many capacitors of an array of capacitors if formed within the phase-locked loop circuit should be coupled to provide the coarse frequency control.