Abstract: A power amplifier impedance adjustment circuit is disclosed. In one aspect, the impedance adjustment circuit includes an input node configured to receive a radio frequency (RF) signal from a power amplifier, an output node configured to provide the RF signal to an antenna switch die, a plurality of electrical components arranged between the input node and the output node, and at least one switch configured to selectively electrically connect at least one of the electrical components to the input node and the output node. For each state of the at least one switch, the impedance adjustment circuit is configured to adjust an impedance of the power amplifier from a natural tune point in a direction towards a target tuned impedance point when viewed on a Smith chart.

Abstract: A method of adjusting an impedance of a power amplifier of a radio frequency system for matching with an antenna switch die is disclosed. In one aspect, the method includes connecting the power amplifier to the antenna switch die via an impedance adjustment circuit, the impedance adjustment circuit including an input node, an output node, a plurality of electrical components arranged between the input node and the output node, and at least one switch configured to selectively electrically connect at least one of the electrical components to the input node and the output node. The method further includes determining an Error Vector Magnitude of the radio frequency system for each of a plurality of states of the at least one switch, and controlling the at least one switch to enter the state of the plurality of states that minimizes the Error Vector Magnitude of the radio frequency system.

Abstract: A front end module having transmit loopback functionality may be operated by conducting a loopback signal from an output of a power amplifier to a receive port on a transmit loopback path and conducting a radio frequency receive signal from an antenna port to the receive port on a receive path. The transmit loopback path includes a first switch coupled between the output of the power amplifier and the receive port. The receive path includes a second switch coupled between the antenna port, where the receive port and is without the first switch.

Abstract: A front end module having transmit loopback functionality may be operated by conducting a loopback signal from an output of a power amplifier to a receive port on a transmit loopback path and conducting a radio frequency receive signal from an antenna port to the receive port on a receive path. The transmit loopback path includes a first switch coupled between the output of the power amplifier and the receive port. The receive path includes a second switch coupled between the antenna port, where the receive port and is without the first switch.

Abstract: A front end module with transmit loopback functionality has a transmit loopback path that is configured to conduct a loopback signal from an output of a power amplifier to a receive port, and a receive path that is configured to conduct a radio frequency receive signal from an antenna port to the receive port. The transmit loopback path includes a first switch coupled between the output of the power amplifier and the receive port. The receive path includes a second switch coupled between the antenna port and the receive port, where the receive path is without the first switch.

Abstract: A front end module having transmit loopback functionality may be operated by conducting a loopback signal from an output of a power amplifier to a receive port on a transmit loopback path and conducting a radio frequency receive signal from an antenna port to the receive port on a receive path. The transmit loopback path includes a first switch coupled between the output of the power amplifier and the receive port. The receive path includes a second switch coupled between the antenna port, where the receive port and is without the first switch.

Abstract: A front end module with transmit loopback functionality has a transmit loopback path that is configured to conduct a loopback signal from an output of a power amplifier to a receive port, and a receive path that is configured to conduct a radio frequency receive signal from an antenna port to the receive port. The transmit loopback path includes a first switch coupled between the output of the power amplifier and the receive port. The receive path includes a second switch coupled between the antenna port and the receive port, where the receive path is without the first switch.

Abstract: A front end module having transmit loopback functionality may be operated by conducting a loopback signal from an output of a power amplifier to a receive port on a transmit loopback path and conducting a radio frequency receive signal from an antenna port to the receive port on a receive path. The transmit loopback path includes a first switch coupled between the output of the power amplifier and the receive port. The receive path includes a second switch coupled between the antenna port, where the receive port and is without the first switch.