Amplifier noise cancellation

1. A power amplifier circuit comprising:

a transistor having a first terminal that is configured to receive an input signal, a second terminal electrically coupled to ground, and a third terminal configured to transmit a combined amplified signal; and

a combining signal input path electrically coupled to the second terminal and configured to receive a noise-cancellation signal that is inversely matched to a noise signal present in the input signal and provide the noise-cancellation signal to the second terminal of the transistor to generate, at least in part, the combined amplified signal.

2. The power amplifier circuit of claim 1 , wherein the noise-cancellation signal is injected into a signal path of the transistor utilizing the second terminal of the transistor.

3. The power amplifier circuit of claim 1 , wherein the transistor is an amplifying transistor of a low-noise amplifier.

4. The power amplifier circuit of claim 1 , wherein the first terminal of the transistor is not loaded with the noise-cancellation signal.

5. The power amplifier circuit of claim 1 , wherein the noise-cancellation signal prevents noise from entering the transistor and being amplified by the transistor.

6. The power amplifier circuit of claim 1 , wherein no separate signal combiner is coupled to the first terminal of the transistor.

7. The power amplifier circuit of claim 1 , further comprising a cascode transistor coupled to the third terminal of the transistor.

8. The power amplifier circuit of claim 1 , wherein the combining signal input path includes a buffer amplifier.

9. The power amplifier circuit of claim 1 , wherein the transistor is a field-effect transistor.

10. The power amplifier circuit of claim 1 , further comprising one or more passive devices coupled to the second terminal of the transistor between the second terminal and a ground reference.

11. The power amplifier circuit of claim 10 , wherein the one or more passive devices comprise an inductor.

12. A method of manufacturing a power amplifier module, the method comprising:

providing a semiconductor substrate;

forming a transistor on the semiconductor substrate, the transistor having a first terminal, a second terminal, and a third terminal;

electrically coupling the first terminal to an input signal node;

electrically coupling the second terminal to a ground reference node;

electrically coupling a third terminal to an output signal path;

forming a combining signal input path; and

coupling the combining signal input path to the second terminal of the transistor, the combining signal input path being configured to receive a noise-canceling signal that is inversely matched at least in part to a noise signal component of a radio-frequency input signal present at the input signal node.

13. The method of claim 12 , further comprising forming a cascode transistor on the semiconductor substrate.

14. The method of claim 13 , further comprising electrically coupling the third terminal of the transistor to a terminal of the cascode transistor.

15. The method of claim 12 , wherein the transistor is a field-effect transistor.

16. The method of claim 12 , further comprising coupling an inductor to the second terminal of the transistor and coupling the inductor to the ground reference node, the second terminal being electrically coupled to the ground reference node through the inductor.

17. A method of cancelling noise in a power amplifier module, the method comprising:

providing a radio-frequency input signal on a first terminal of a transistor device, the radio-frequency input signal including a noise component;

providing a noise-cancellation signal on a noise-cancellation path coupled to a second terminal of the transistor device, the noise-cancellation signal being configured to cancel-out the noise component of the radio-frequency input signal;

cancelling the noise component of the radio-frequency input signal by injecting the noise-cancellation signal in the second terminal of the transistor device to generate a combined signal;

amplifying the combined signal to generate an output signal utilizing the transistor device; and

providing the output signal on a third terminal of the transistor device.

18. The method of claim 17 , further comprising providing the output signal to a terminal of a cascode transistor.

19. The method of claim 17 , further comprising buffering the noise-cancellation path using a buffer amplifier.

20. The method of claim 17 , wherein a grounding path couples the second terminal of the transistor device to a ground reference, the grounding path including an inductor.