Radio front end module with reduced loss and increased linearity
A Radio Frequency (RF) circuit including a receive path, a transmit path, a switching circuit, and an output configured to receive RF signals from an antenna in a receive mode of operation, and to provide RF signals to the antenna in a transmit mode of operation. The receive path is configured to be coupled between a low-noise amplifier and the output. The switching circuit is located in the receive path and is configured, in the receive mode, to selectively couple the low-noise amplifier to the output and to pass the received RF signals from the output to the low-noise amplifier. The transmit path is configured to be coupled between a power amplifier and the output, to provide, in the transmit mode, signals from the power amplifier to the output, bypassing the switching circuit, and to have, in receive mode of operation, an off-state impedance of at least 200+j*13 Ohm.
1. A front-end module for a wireless device comprising:
an input port configured to receive an input Radio Frequency (RF) signal;
a power amplifier coupled to the input port and configured to amplify, in a transmit mode of operation, the input RF signal to provide a first RF signal and, in a receive mode of operation, to have an off-state impedance of at least 200+j*13 Ohm;
an output configured to be coupled to an antenna, to receive a second RF signal from the antenna in the receive mode of operation, and to transmit the first RF signal from the power amplifier to the antenna in the transmit mode of operation;
a low-noise amplifier configured, in the receive mode of operation, to amplify the second RF signal received from the output;
an output port configured to receive the amplified second RF signal from the low-noise amplifier;
a receive path coupled between the low-noise amplifier and the output;
a switching circuit located in the receive path and configured, in the receive mode of operation, to selectively couple the low-noise amplifier to the output and to pass the second RF signal from the output to the low-noise amplifier;
a transmit path coupled between the power amplifier and the output and configured to provide, in the transmit mode of operation, the first RF signal from the power amplifier to the output, bypassing the switching circuit; and
a controller coupled to the switching circuit, the power amplifier, and the low-noise amplifier, the controller being configured to operate the switching circuit to close in the receive mode of operation and to open in the transmit mode of operation, the controller further being configured to transmit an enable control signal to the low-noise amplifier and a disable control signal to the power amplifier in the receive mode of operation.
2. The front-end module of claim 1 wherein the switching circuit is a Single-Pole, Single-Throw (SPST) switch.
3. The front-end module of claim 1 wherein the switching circuit includes:
a first switch selectively coupled between the low-noise amplifier and the output and configured to couple, in the receive mode of operation, the low-noise amplifier to the output, and
a second switch selectively coupled between the low-noise amplifier and ground and configured to couple, in the transmit mode of operation, the low-noise amplifier to ground.
4. The front-end module of claim 1 wherein the switching circuit is further configured, in the transmit mode of operation, to decouple the output from the low-noise amplifier.
5. The front-end module of claim 1 wherein the controller is further configured, in the transmit mode of operation, to transmit an enable control signal to the power amplifier and a disable control signal to the low-noise amplifier.
6. The front-end module of claim 1 wherein in operating the switching circuit to open in the transmit mode of operation, the controller is further configured to:
operate the switching circuit to open;
transmit an enable control signal to the power amplifier in response to the switching circuit opening; and
transmit a disable control signal to the low-noise amplifier in response to the power amplifier being enabled.
7. The front-end module of claim 1 wherein in operating the switching circuit to close in the receive mode of operation, the controller is further configured to:
transmit a disable control signal to the power amplifier;
operate the switching circuit to close in response to the power amplifier being disabled; and
transmit an enable control signal to the low-noise amplifier in response to the switching circuit closing.
8. The front-end module of claim 1 wherein the low-noise amplifier includes an impedance matching network and wherein the switching circuit, the impedance matching network, and the low-noise amplifier are integrated in a single integrated circuit.
9. The front-end module of claim 1 wherein the power amplifier, the low-noise amplifier and the switching circuit are integrated in a single die of an integrated circuit.
10. The front-end module of claim 1 wherein the input RF signal is a millimeter wave input RF signal and the power amplifier is further configured to amplify the millimeter wave input RF signal.
11. The front-end module of claim 1 wherein the input RF signal has a frequency in a 34-36 GHz range and the power amplifier is further configured to amplify the input RF signal having a frequency in the 34-36 GHz range.
12. The front-end module of claim 1 wherein the power amplifier includes:
at least one differential amplifier;
at least one input balun coupled between the at least one differential amplifier and the input port; and
at least one output balun coupled between the at least one differential amplifier and the output.
13. The front-end module of claim 12 wherein the at least one input balun and the at least one output balun have an impedance of about 300 picohenries.
14. The front-end module of claim 12 wherein the power amplifier further includes:
a first 90° hybrid circuit coupled between the input port and the at least one input balun; and
a second 90° hybrid circuit coupled between the at least one output balun and the output.
15. The front-end module of claim 14 wherein the at least one differential amplifier includes a first differential amplifier and a second differential amplifier, and the at least one input balun includes a first balun coupled between the first differential amplifier and the first 90° hybrid circuit, and a second balun coupled between the second differential amplifier and the first 90° hybrid circuit.
16. The front-end module of claim 15 wherein the at least one output balun includes a third balun coupled between the first differential amplifier and the second 90° hybrid circuit, and a fourth balun coupled between the second differential amplifier and the second 90° hybrid circuit.
17. The front-end module of claim 1 wherein the low-noise amplifier includes a differential amplifier, a first balun coupled between the differential amplifier and the output, and a second balun coupled between the differential amplifier and the output port.
18. A front-end module for a wireless device comprising:
an input port configured to receive an input Radio Frequency (RF) signal;
a power amplifier coupled to the input port and configured to amplify, in a transmit mode of operation, the input RF signal to provide a first RF signal, the power amplifier including at least one differential amplifier;
an output configured to be coupled to an antenna, to receive a second RF signal from the antenna in the receive mode of operation, and to transmit the first RF signal from the power amplifier to the antenna in the transmit mode of operation;
at least one input balun coupled between the at least one differential amplifier and the input port;
at least one output balun coupled between the at least one differential amplifier and the output;
a low-noise amplifier configured, in the receive mode of operation, to amplify the second RF signal received from the output;
an output port configured to receive the amplified second RF signal from the low-noise amplifier;
a receive path coupled between the low-noise amplifier and the output;
a switching circuit located in the receive path and configured, in the receive mode of operation, to selectively couple the low-noise amplifier to the output and to pass the second RF signal from the output to the low-noise amplifier;
a transmit path coupled between the power amplifier and the output and configured to provide, in the transmit mode of operation, the first RF signal from the power amplifier to the output, bypassing the switching circuit; and
a semiconductor die on which the power amplifier, the low-noise amplifier, and the switching circuit are integrated into a single package.
19. The front-end module of claim 18 , wherein the semiconductor die is a CMOS die.
20. The front-end module of claim 18 wherein the power amplifier further includes:
a first 90° hybrid circuit coupled between the input port and the at least one input balun; and
a second 90° hybrid circuit coupled between the at least one output balun and the output.
21. The front-end module of claim 20 wherein the at least one differential amplifier includes a first differential amplifier and a second differential amplifier, and the at least one input balun includes a first balun coupled between the first differential amplifier and the first 90° hybrid circuit, and a second balun coupled between the second differential amplifier and the first 90° hybrid circuit.
22. The front-end module of claim 21 wherein the at least one output balun includes a third balun coupled between the first differential amplifier and the second 90° hybrid circuit, and a fourth balun coupled between the second differential amplifier and the second 90° hybrid circuit.
23. A front-end module for a wireless device comprising:
an input port configured to receive an input Radio Frequency (RF) signal;
a power amplifier coupled to the input port and configured to amplify, in a transmit mode of operation, the input RF signal to provide a first RF signal;
an output configured to be coupled to an antenna, to receive a second RF signal from the antenna in the receive mode of operation, and to transmit the first RF signal from the power amplifier to the antenna in the transmit mode of operation;
a low-noise amplifier configured, in the receive mode of operation, to amplify the second RF signal received from the output, the low-noise amplifier including a differential amplifier;
an output port configured to receive the amplified second RF signal from the low-noise amplifier;
a first balun coupled between the differential amplifier and the output;
a second balun coupled between the differential amplifier and the output port;
a receive path coupled between the low-noise amplifier and the output;
a switching circuit located in the receive path and configured, in the receive mode of operation, to selectively couple the low-noise amplifier to the output and to pass the second RF signal from the output to the low-noise amplifier;
a transmit path coupled between the power amplifier and the output and configured to provide, in the transmit mode of operation, the first RF signal from the power amplifier to the output, bypassing the switching circuit; and
a semiconductor die on which the power amplifier, the low-noise amplifier, and the switching circuit are integrated into a single package.
24. The front-end module of claim 18 wherein the input RF signal is a millimeter wave input RF signal and the power amplifier is further configured to amplify the millimeter wave input RF signal.
25. The front-end module of claim 18 wherein the input RF signal has a frequency in a 34-36 GHz range and the power amplifier is further configured to amplify the input RF signal having a frequency in the 34-36 GHz range.