Configurable wideband split LNA
Methods and devices addressing design of wideband LNAs with gain modes are disclosed. The disclosed teachings can be used to reconfigure RF receiver front-end to operate in various applications imposing stringent and conflicting requirements. Wideband and narrowband input and output matching with gain modes using a combination of the same hardware and a switching network are also disclosed. The described methods and devices also address carrier aggregation requirements and provide solutions that can be used both in single-mode and split-mode operations.
1. A radio frequency (RF) receiver front-end comprising:
a first amplifying element;
a first configurable output matching network comprising a first source follower amplifier stage; and
a second configurable output matching network comprising a second source follower amplifier stage,
wherein:
the first and the second output matching networks are each coupled to a drain terminal of the first amplifying element, and
the first and the second source follower amplifier stages are each configured to selectively be in an active or inactive state;
in a first single-mode state, the first source follower amplifier stage is in the active state and the second source follower amplifier stage is in the inactive state; and
in a second single-mode state, the first source follower amplifier stage is in the inactive state and the second source follower amplifier stage is in the active state.
2. The RF receiver front-end of claim 1 , further comprising a third source follower amplifier stage connected to a source terminal of the first source follower amplifier stage.
3. The RF front-end of claim 2 , further comprising a fourth source follower amplifier stage connected to a source terminal of the second source follower amplifier stage.
4. The RF receiver front-end of claim 1 , further comprising a second amplifying element having a drain terminal connected to the drain terminal of the first amplifying element.
5. The RF receiver front-end of claim 4 configured to receive a first RF signal at an input of the first amplifying element, and to receive a second RF signal at an input of the second amplifying element, the second RF signal being different from the first RF signal.
6. A radio frequency (RF) receiver front-end comprising:
a first amplifying element;
a first output matching network coupled to a drain terminal of the first amplifying element, the first configurable output matching network comprising a first source follower amplifier stage;
a second output matching network coupled to the drain terminal of the first amplifying element, the second configurable output matching network comprising a second source follower amplifier stage,
wherein:
in a first single-mode state, the first source follower amplifier stage is in an active state and the second source follower amplifier stage is in an inactive state; and
in a second single-mode state, the first source follower amplifier stage is in the inactive state and the second source follower amplifier stage is in the active state.
7. The RF receiver front-end of claim 6 , wherein in a split-mode state, the first and the second source follower amplifier stages are in the active state.
8. The RF receiver front-end of claim 7 , further comprising a first cascode transistor coupling the first amplifying element to the first source follower amplifier stage.
9. The RF receiver front-end of claim 8 , further comprising a second cascode transistor coupling the second source follower amplifier stage to the first amplifying element.
10. The RF receiver front-end of claim 9 , wherein:
in the first single-mode state, the first cascode transistor is in the active state and the second cascode transistor is in the inactive state;
in the second single-mode state, the first cascode transistor is in the inactive state and the second cascode transistor in the active state.
11. The RF receiver front-end of claim 10 , wherein in the split-mode state, the first and the second cascode transistors are in the active state.
12. The RF receiver front-end of claim 11 , wherein a bandwidth and a gain of the RF receiver front-end are adjustable based on states of the first and the second source follower amplifier stages and configuration state of the first and the second configurable output matching networks.
13. The RF receiver front-end of claim 12 , further comprising a configurable input matching network coupled with the first amplifying element, and wherein the bandwidth and the gain of the RF receiver front-end are adjustable based on a configuration of the configurable input matching network.
14. The RF receiver of claim 13 , wherein the configuration states of the input, the first, and the second configurable output matching networks and the states of the first and the second source follower amplifier stages are controlled by a switching network.
15. The RF receiver of claim 13 , wherein the configurable input, the first, and the second output matching networks comprise selectively switchable capacitors and inductors.
16. The RF receiver front-end of claim 15 , wherein the switching network configures or reconfigures the RF receiver front-end to operate at one or more frequency ranges comprising at least a narrowband, an extended narrowband and a wideband frequency range.
17. The RF receiver front-end of claim 16 , wherein the switching network comprises:
a first switch coupling a gate terminal of the first cascode transistor to ground, and
a second switch coupling a gate terminal of the second cascode transistor to ground.
18. The RF receiver front-end of claim 17 , where the switching network further comprises:
a third switch coupling a source terminal of the first source follower amplifying stage to ground, and
a fourth switch coupling a source terminal of the second source follower amplifying stage to ground.
19. The RF receiver front-end of claim 18 , wherein:
in the first single-mode state, the first and the third switches are closed, and the second and the fourth switches are open, and
in the second single-mode state, the first and the third switches are open, and the second and the fourth switches are closed.
20. The RF receiver front-end of claim 19 , wherein in the split-mode all the switches of the switching network are closed.