Amplifier architecture reconfiguration

1. A device comprising:

first, second, and third inputs, each configured to receive an RF signal;

first and second amplifiers; and

an input phase adjustment circuit coupling the first, second, and third inputs to the first and second amplifiers, the input phase adjustment circuit having first and second outputs coupled to the first and second amplifiers, respectively, the input phase adjustment circuit comprising:

a pair of inputs for the first output, where the pair of inputs includes the first and second inputs;

a first phase adjustment path coupling the first input to the first output, wherein the first phase adjustment path imparts a first phase delay to the RF signal conducted through the first phase adjustment path; and

a second phase adjustment path coupling the second input to the first output, wherein the second phase adjustment path imparts a second phase delay to the RF signal conducted through the second phase adjustment path, and wherein the first and second phase delays are fixed and are different from each other by a multiple of 90 degrees.

2. The device of claim 1 , wherein the input phase adjustment circuit comprises:

a further pair of inputs for the second output, wherein the further pair of inputs includes the third input and a fourth input; and

a further pair of phase adjustment paths coupling the further pair of inputs to the second output, respectively;

wherein the further pair of phase adjustment paths are configured to adjust a phase of the RF signal for the second output differently.

3. The device of claim 1 , wherein the first phase adjustment path comprises a delay element to effectuate at least a 90 degree phase adjustment of the RF signal.

4. The device of claim 1 , wherein:

an RF input port is coupled to the first input of the pair of inputs;

the first input is coupled to the first phase adjustment path;

the second input of the pair of inputs is electrically tied to ground and coupled to the second phase adjustment path; and

the second phase adjustment path comprises a delay element to effectuate at least a 90 degree phase adjustment.

5. The device of claim 4 , wherein:

the first amplifier is configured as a carrier amplifier in a Doherty architecture; and

the second amplifier is configured as a peaking amplifier in the Doherty architecture.

6. The device of claim 1 , wherein:

the first input of the pair of inputs is not coupled to an RF input port such that the first phase adjustment path is floating;

the RF input port is coupled to the second input of the pair of inputs;

the second input is coupled to the second phase adjustment path; and

the second phase adjustment path comprises a delay element to effectuate a 90 degree phase adjustment.

7. The device of claim 1 , wherein:

the first amplifier is configured as a carrier amplifier in a Doherty architecture;

the second amplifier is configured as a peaking amplifier in the Doherty architecture.

8. The device of claim 1 , further comprising a third amplifier, wherein:

the second amplifier is coupled to a second pair of phase adjustment paths of the input phase adjustment circuit;

the third amplifier is coupled to a third pair of phase adjustment paths of the input phase adjustment circuit;

the input phase adjustment circuit comprises a second pair of inputs for the second pair of phase adjustment paths;

the input phase adjustment circuit comprises a third pair of inputs for the third pair of phase adjustment paths; and

an RF input port is coupled to selected inputs of the pair of inputs for the first output, the second pair of inputs, and the third pair of inputs such that the first, second, and third amplifiers are disposed in a three-way Doherty architecture.

9. The device of claim 1 , wherein:

the input phase adjustment circuit comprises a first delay element coupled to the first output and a second delay element coupled to the first output via the first delay element;

the first input of the pair of inputs is coupled to the first delay element to include the first delay element in the first phase adjustment path and bypass the second delay element; and

the second input of the pair of inputs is coupled to the second delay element to include the first and second delay elements in the second phase adjustment path.

10. The device of claim 9 , wherein:

the first delay element is configured such that the first phase adjustment path has at least a 90 degree phase delay; and

the first and second delay elements are configured such that the second phase adjustment path has at least a 180 degree phase delay.

11. The device of claim 9 , wherein the first and second inputs are coupled to an RF input port and ground, respectively, such that the phase of the RF signal is adjusted via the first phase adjustment path to present at least a 90 degree phase delay.

12. The device of claim 9 , wherein the first and second inputs are floating and coupled to an RF input port, respectively, such that the phase of the RF signal is adjusted via the first phase adjustment path to present at least a 180 degree phase delay.

13. A device comprising:

a first integrated circuit assembly that comprises a first amplifier, an unconnected amplifier, and a first input phase adjustment circuit, wherein the first input phase adjustment circuit couples first and second inputs to the first amplifier;

a second integrated circuit assembly that comprises a second amplifier and a third amplifier and a second input phase adjustment circuit, wherein the second input phase adjustment circuit couples third and fourth inputs to the second amplifier and couples a fifth input to the third amplifier; and

the first input phase adjustment circuit and the second input phase adjustment circuit are configured to establish a three-way, inverted Doherty architecture in which:

at least a 180 degree phase delay is established for the first amplifier;

at least a 90 degree phase delay is established for the second amplifier; and

an effective 0 degree phase delay is established for the third amplifier.

14. A Doherty amplifier to amplify an RF signal, the Doherty amplifier comprising:

a carrier amplifier;

a peaking amplifier; and

an input phase adjustment circuit coupled to the carrier and peaking amplifiers, the input phase adjustment circuit having first and second outputs coupled to the carrier and peaking amplifiers, respectively, the input phase adjustment circuit comprising:

a first pair of inputs;

a second pair of inputs;

a first pair of phase adjustment paths coupled to the first pair of inputs and to the first output; and

a second pair of phase adjustment paths coupled to the second pair of inputs and to the second output;

wherein, for the carrier amplifier, the RF signal is provided to only one input of the first pair of inputs to select one of the first pair of phase adjustment paths and establish a first phase adjustment of the RF signal between the one input of the first pair of inputs and the first output, and for the peaking amplifier, the RF signal is provided to only one input of the second pair of inputs to select one of the second pair of phase adjustment paths and establish a second phase adjustment of the RF signal between the one input of the second pair of inputs and the second output, and wherein the first and second phase adjustments are different from each other by a multiple of 90 degrees.

15. The Doherty amplifier of claim 14 , wherein each pair of phase adjustment paths comprises a path configured to introduce at least a 90 degree phase shift.

16. The Doherty amplifier of claim 15 , further comprising a phase delay element disposed between the RF input port and the input of the pair of inputs for the first output and coupled to the path configured to introduce the at least 90 degree phase shift, wherein the phase delay element is configured to introduce a further at least 90 degree phase shift.

17. The Doherty amplifier of claim 14 , wherein, for each output of the first and second outputs:

the input phase adjustment circuit comprises a first delay element coupled to the output and a second delay element coupled to the output via the first delay element;

a first input of the pair of inputs is coupled to the first delay element to include the first delay element in a first phase adjustment path of the pair of phase adjustment paths and bypass the second delay element; and

a second input of the pair of inputs is coupled to the second delay element to include the first and second delay elements in a second adjustment path of the pair of phase adjustment paths.

18. A method of fabricating an amplifier, the method comprising:

providing an amplifier die;

providing an input phase adjustment circuit that comprises a first input, a second input, an output, a first phase adjustment path coupling the first input to the output, and a second phase adjustment path coupling the second input to the output;

coupling the output of the input phase adjustment circuit to the amplifier die; and

coupling an RF input port to only one of the first or second inputs to couple one of the first or second phase adjustment paths between the only one of the first or second inputs and the output of the input phase adjustment circuit so that the amplifier is configured to adjust a phase of an RF signal received at the only one of the first or second inputs by a phase delay that the first or second phase adjustment path is configured to present, and wherein first and second phase delays imparted by the first and second phase adjustment paths are fixed and are different from each other by a multiple of 90 degrees.

19. The method of claim 18 , further comprising coupling the other one of the first or second inputs to ground, wherein:

the phase adjustment path to which the other one of the first or second inputs is coupled is configured to present at least a 90 degree phase shift; and

coupling the output comprises connecting the output to a carrier amplifier on the amplifier die.