RF circuit with balanced amplifier, receive amplifier, and output directional coupler

A radio frequency (RF) circuit for an RF front-end, the RF circuit comprising:

• an input-output terminal configured to be coupled to an antenna;
• a receiver amplifier with an input and an output;
• a balanced amplifier that includes
• an input directional coupler comprising first, second, third, and fourth ports,
• an output directional coupler comprising first, second, third, and fourth ports, wherein the first port of the output directional coupler is coupled to the input-output terminal, and the fourth port of the output directional coupler is coupled to the input of the receiver amplifier,
• a first transmit amplifier, wherein an input of the first transmit amplifier is coupled to the third port of the input directional coupler, and the second port of the output directional coupler is coupled to an output of the first transmit amplifier,
• a second transmit amplifier, wherein an input of the second transmit amplifier is coupled to the second port of the input directional coupler, and the third port of the output directional coupler is coupled to an output of the second transmit amplifier,
• a first output matching network arranged between the output of the first transmit amplifier and the second port of the output directional coupler, wherein the first output matching network includes
• a first inductor having a first inductor first terminal coupled to the output of the first transmit amplifier and a first inductor second terminal configured to be coupled to a supply voltage in the transmit mode of operation and to a ground in the receive mode of operation, and
• a second output matching network arranged between the output of the second transmit amplifier and the third port of the output directional coupler, wherein the second output matching network includes
• a second inductor having a second inductor first terminal coupled to the output of the second transmit amplifier and a second inductor second terminal configured to be coupled to the supply voltage in the transmit mode of operation and to the ground in the receive mode of operation, and
• wherein the RF circuit is configured in a transmit mode of operation to transmit an RF signal to the input-output terminal and in a receive mode of operation to couple an RF signal received on the first port of the output directional coupler to an input of the receiver amplifier.

A radio frequency (RF) circuit for an RF front-end, the RF circuit comprising:

• an input-output terminal configured to be coupled to an antenna;
• an RF terminal;
• a receiver amplifier with an input and an output;
• and
• a balanced amplifier that includes
• an input directional coupler comprising first, second, third, and fourth ports, wherein the fourth port of the input directional coupler is configured to be coupled to an isolation impedance,
• an output directional coupler comprising first, second, third, and fourth ports,
• a first transmit amplifier, and
• a second transmit amplifier,
• wherein
• an input of the first transmit amplifier is coupled to the third port of the input directional coupler,
• an input of the second transmit amplifier is coupled to the second port of the input directional coupler,
• the first port of the output directional coupler is coupled to the input-output terminal, the second port of the output directional coupler is coupled to an output of the first transmit amplifier, the third port of the output directional coupler is coupled to an output of the second transmit amplifier, and the fourth port of the output directional coupler is coupled to the input of the receiver amplifier,
• the RF circuit is configured in a transmit mode of operation to transmit an RF signal to the input-output terminal and in a receive mode of operation to couple an RF signal received on the first port of the output directional coupler to an input of the receiver amplifier, and
• the RF circuit is further configured in the transmit mode to switchably couple the input of the balanced amplifier to the RF terminal, and in the receive mode to switchably couple the output of the receiver amplifier to the RF terminal.