Low-noise amplifier

1. A receiver circuit comprising:

a common source or common emitter low-noise amplifier (LNA) circuit for amplifying signals at an operating frequency f; and

a termination circuit with a current input terminal connected to the output terminal of the LNA circuit,

wherein the LNA circuit comprises:

an input transistor arranged to, in operation, be biased to have a transconductance g m at the operating frequency f, and having a first terminal, which is a gate or base terminal, operatively connected to an input terminal of the LNA circuit;

a shunt-feedback capacitor operatively connected between the first terminal of the input transistor and a second terminal, which is a drain or collector terminal, of the input transistor; and

an output capacitor operatively connected between the second terminal of the input transistor and an output terminal of the LNA circuit,

wherein the magnitude |Z in (f)| of the input impedance Z in of the termination circuit at the frequency f is less than 1/10 of the magnitude |Z C L (f)=1/(2π·C L ) of the impedance Z C L (f) of the output capacitor of the LNA circuit, wherein C L is a capacitance value of the output capacitor.

2. The receiver circuit according to claim 1 , wherein the input transistor is a MOS transistor, the first terminal is a gate terminal, the second terminal is a drain terminal, and the LNA circuit is a common source LNA circuit.

3. The receiver circuit according to claim 2 , wherein the shunt-feedback capacitor is or comprises a MOS gate capacitor implemented with a MOS transistor of the same type as the input transistor.

4. The receiver circuit according to claim 2 , wherein the feedback capacitor is or comprises a gate-to-drain capacitance of the input transistor.

5. The receiver circuit according to claim 1 , wherein the input transistor is a bipolar junction transistor, the first terminal is a base terminal, the second terminal is a collector terminal, and the LNA circuit is a common emitter LNA circuit.

6. The receiver circuit according to claim 1 , further comprising a series inductor operatively connected between the first terminal of the input transistor and the input terminal of the LNA circuit.

7. The receiver circuit according to claim 1 , wherein the receiver circuit is a radio receiver circuit.

8. A radio communication apparatus comprising the receiver circuit according to claim 7 .

9. The radio communication apparatus according to claim 8 , wherein the radio communication apparatus is a mobile terminal or a wireless data modem.

10. The radio communication apparatus according to claim 8 , wherein the radio communication apparatus is a radio base station.

11. A wireline communication apparatus comprising the receiver circuit according to claim 1 .

12. The wireline communication apparatus according to claim 11 , wherein the wireline communication apparatus is a cable modem.

13. The receiver circuit of claim 1 , wherein the capacitance value C L of the output capacitor satisfies C L <g m /f.

14. A receiver circuit comprising:

a common source or common emitter low-noise amplifier (LNA) circuit for amplifying signals at an operating frequency f; and

a termination circuit with a current input terminal connected to the output terminal of the LNA circuit,

wherein the LNA circuit comprises:

an input transistor arranged to, in operation, be biased to have a transconductance g m at the operating frequency f, and having a first terminal, which is a gate or base terminal, operatively connected to an input terminal of the LNA circuit;

a shunt-feedback capacitor operatively connected between the first terminal of the input transistor and a second terminal, which is a drain or collector terminal, of the input transistor; and

an output capacitor operatively connected between the second terminal of the input transistor and an output terminal of the LNA circuit,

wherein the termination circuit is or comprises a common-base amplifier, a common-gate amplifier, a trans-impedance amplifier, a feedback-connected operational amplifier with a virtual-ground node as current input terminal, a transformer, or a current-mode mixer.

15. The receiver circuit of claim 14 , wherein the output capacitor has a capacitance value C L <g m /f.

16. The receiver circuit according to claim 14 , wherein the input transistor is a MOS transistor, the first terminal is a gate terminal, the second terminal is a drain terminal, and the LNA circuit is a common source LNA circuit.

17. The receiver circuit according to claim 16 , wherein the shunt-feedback capacitor is or comprises a MOS gate capacitor implemented with a MOS transistor of the same type as the input transistor.

18. The receiver circuit according to claim 16 , wherein the feedback capacitor is or comprises a gate-to-drain capacitance of the input transistor.

19. The receiver circuit according to claim 14 , wherein the input transistor is a bipolar junction transistor, the first terminal is a base terminal, the second terminal is a collector terminal, and the LNA circuit is a common emitter LNA circuit.

20. The receiver circuit according to claim 14 , further comprising a series inductor operatively connected between the first terminal of the input transistor and the input terminal of the LNA circuit.

21. The receiver circuit according to claim 14 , wherein the receiver circuit is a radio receiver circuit.

22. A radio communication apparatus comprising the receiver circuit according to claim 21 .

23. The radio communication apparatus according to claim 22 , wherein the radio communication apparatus is a mobile terminal or a wireless data modem.

24. The radio communication apparatus according to claim 22 , wherein the radio communication apparatus is a radio base station.

25. A wireline communication apparatus comprising the receiver circuit according to claim 14 .

26. The wireline communication apparatus according to claim 25 , wherein the wireline communication apparatus is a cable modem.