Low-noise amplifier, in particular for a cellular mobile telephone

• US 6,639,468 B2
• Filed: 06/21/2001
• Issued: 10/28/2003
• Est. Priority Date: 07/12/2000
• Status: Expired due to Term

• Current Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Inventors: Belot, Didier
• Primary Examiner(s): LAM, TUAN THIEU
• Application Number:
  US09/886,852
• Publication Number:
  US 20020027475A1
• Time in Patent Office: 859 Days
• Field of Search: 330/252, 330/254, 330/302, 330/305, 330/310, 330/311
• US Class Current: 330/252
• CPC Class Codes: H03F 2200/294 the amplifier being a low noise amplifier [LNA]
• CPC Class Codes: H03F 2200/372 Noise reduction and elimination in amplifier
• CPC Class Codes: H03F 2203/45316 the AAC comprising one or more discrete inductive elements or coils
• CPC Class Codes: H03F 2203/45386 the AAC comprising one or more coils in the source circuit
• CPC Class Codes: H03F 2203/45554 the IC comprising one or more coils
• CPC Class Codes: H03F 2203/45704 the LC comprising one or more parallel resonance circuits
• CPC Class Codes: H03F 3/191 Tuned amplifiers H03F3/193, H03F3/195 take precedence
• CPC Class Codes: H03F 3/45089 Non-folded cascode stages

Abstract

The amplifier includes an input amplifier stage, an output amplifier stage cascode-connected with the input amplifier stage, and a load stage connected to the output stage. The load stage includes a plurality of circuits each including a capacitive component and an inductive component having a Q greater than 10, and having respective different resonant frequencies. All the gain curves respectively associated with all the circuits have, to within a stated tolerance, the same maximum gain value at the resonant frequencies. The gain curves respectively associated with two circuits having respective immediately adjacent resonant frequencies overlap below a threshold 3 dB, to within a stated tolerance, below the maximum gain value.

Claims

1. An amplifier comprising:

an input amplifier stage;

an output amplifier stage connected to said input amplifier stage; and

a load stage connected to said output amplifier stage and comprising a plurality of circuits, each circuit comprising a capacitive component and an inductive component having a Q greater than 10, and each circuit having a resonant frequency different from a resonant frequency of the other circuits,

each circuit having a gain versus frequency curve such that all the gain versus frequency curves have, to within a tolerance, a same maximum gain value at a respective resonant frequency, and the respective gain versus frequency curves associated with two circuits having immediately adjacent resonant frequencies overlapping below a threshold at 3 dB, to within the tolerance, below the maximum gain value.

2. An amplifier according to claim 1, wherein the tolerance has an absolute value of about 1 dB.

3. An amplifier according to claim 1, wherein said plurality of circuits are connected in series with said output amplifier stage.

4. An amplifier according to claim 1, wherein each circuit has at their respective resonant frequency a first impedance value that is the same as the first impedance values of the other circuits, to within a second tolerance.

5. An amplifier according to claim 4, wherein two circuits associated with two immediately adjacent resonant frequencies have at a median frequency between their two resonant frequencies a same second impedance value equal to half the first impedance value, to within the second tolerance.

6. An amplifier according to claim 5, wherein the second tolerance is equal to about 20 %.

7. An amplifier according to claim 1, wherein said capacitive component and said inductive component for each circuit are connected in parallel.

8. An amplifier according to claim 7, wherein said inductive components for each circuit are equal.

9. An amplifier according to claim 7, wherein said capacitive components for each circuit are equal.

10. An amplifier according to claim 1, wherein said input amplifier stage comprises a first pair of transistors to define a differential input amplifier stage;

and wherein said output amplifier stage comprises a second pair of transistors to define a differential output amplifier stage.

11. An amplifier according to claim 10, wherein said plurality of circuits are separated into two groups, with each group connected to a respective transistor of said output amplifier stage.

12. An amplifier according to claim 11, wherein said circuits in each group are connected in series.

13. An amplifier comprising:

an input amplifier stage;

an output amplifier stage connected to said input amplifier stage; and

a load stage comprising a plurality of circuits connected in series with said output amplifier stage, each circuit comprising a capacitive component and an inductive component, and each circuit having a resonant frequency different from a resonant frequency of the other circuits.

14. An amplifier according to claim 13, wherein each circuit has a Q greater than 10.

15. An amplifier according to claim 13, wherein each circuit has a gain versus frequency curve such that all the gain versus frequency curves have, to within a tolerance, a same maximum gain value at a respective resonant frequency, and the respective gain versus frequency curves associated with two circuits having immediately adjacent resonant frequencies overlapping below a threshold at 3 dB, to within the tolerance, below the maximum gain value.

16. An amplifier according to claim 15, wherein the tolerance has an absolute value of about 1 dB.

17. An amplifier according to claim 13, wherein each circuit has at their respective resonant frequency a first impedance value that is the same as the first impedance values of the other circuits, to within a tolerance.

18. An amplifier according to claim 17, wherein two circuits associated with two immediately adjacent resonant frequencies have at a median frequency between their two resonant frequencies a same second impedance value equal to half the first impedance value, to within the tolerance.

19. An amplifier according to claim 17, wherein the tolerance is equal to about 20%.

20. An amplifier according to claim 13, wherein said capacitive component and said inductive component for each circuit are connected in parallel.

21. An amplifier according to claim 13, wherein said input amplifier stage comprises a first pair of transistors to define a differential input amplifier stage;

and wherein said output amplifier stage comprises a second pair of transistors to define a differential output amplifier stage.

22. An amplifier according to claims 21, wherein said plurality of circuits are separated into two groups, with each group connected to a respective transistor of said output amplifier stage.

23. A receiver comprising:

an amplifier comprising

an input amplifier stage,

an output amplifier stage connected to said input amplifier stage, and

a load stage comprising a plurality of circuits connected in series with said output amplifier stage, each circuit comprising a capacitive component and an inductive component, and each circuit having a resonant frequency different from a resonant frequency of the other circuits; and

a tuner connected to said amplifier.

24. A receiver according to claim 23, further comprising a processor connected to said tuner.

25. A receiver according to claim 23, wherein each circuit has a Q greater than 10.

26. A receiver according to claim 23, wherein each circuit has a gain versus frequency curve such that all the gain versus frequency curves have, to within a tolerance, a same maximum gain value at a respective resonant frequency, and the respective gain versus frequency curves associated with two circuits having immediately adjacent resonant frequencies overlapping below a threshold at 3 dB, to within the tolerance, below the maximum gain value.

27. A receiver according to claim 26,wherein the tolerance has an absolute value of about 1 dB.

28. A receiver according to claim 23, wherein each circuit has at their respective resonant frequency a first impedance value that is the same as the first impedance values of the other circuits, to within a tolerance.

29. A receiver according to claim 28, wherein two circuits associated with two immediately adjacent resonant frequencies have at a median frequency between their two resonant frequencies a same second impedance value equal to half the first impedance value, to within the tolerance.

30. A receiver according to claim 28, wherein the tolerance is equal to about 20%.

31. A receiver according to claim 24, wherein the receiver is part of a cellular mobile telephone.

32. A method for making an amplifier comprising:

connecting an output amplifier stage to an input amplifier stage; and

connecting a load stage comprising a plurality of circuits in series with the output amplifier stage, each circuit comprising a capacitive component and an inductive component, and each circuit having a resonant frequency different from a resonant frequency of the other circuits.

33. A method according to claim 32, wherein each circuit has a Q greater than 10.

34. A method according to claim 32, wherein each circuit has a gain versus frequency curve such that all the gain versus frequency curves have, to within a tolerance, a same maximum gain value at a respective resonant frequency, and the respective gain versus frequency curves associated with two circuits having immediately adjacent resonant frequencies overlapping below a threshold at 3 dB, to within the tolerance, below the maximum gain value.

35. A method according to claim 34, wherein the tolerance has an absolute value of about 1 dB.

36. A method according to claim 32, wherein each circuit has at their respective resonant frequency a first impedance value that is the same as the first impedance values of the other circuits, to within a tolerance.

37. A method according to claim 36, wherein two circuits associated with two immediately adjacent resonant frequencies have at a median frequency between their two resonant frequencies a same second impedance value equal to half the first impedance value, to within the tolerance.

38. A method according to claim 36, wherein the tolerance is equal to about 20%.

39. A receiver comprising:

an amplifier comprising

an input amplifier stage,

an output amplifier stage connected to said input amplifier stage, and

a load stage connected to said output amplifier stage and comprising a plurality of circuits, each circuit comprising a capacitive component and an inductive component, and each circuit having a resonant frequency different from a resonant frequency of the other circuits;

each circuit having a gain versus frequency curve such that all the gain versus frequency curves have, to within a tolerance, a same maximum gain value at a respective resonant frequency, and the respective gain versus frequency curves associated with two circuits having immediately adjacent resonant frequencies overlapping below a threshold at 3 dB, to within the tolerance, below the maximum gain value; and

a tuner connected to said amplifier.

40. A receiver according to claim 39, further comprising a processor connected to said tuner.

41. A receiver according to claim 39, wherein each circuit has a Q greater than 10;

and wherein the tolerance has an absolute value of about 1 dB.

42. A receiver according to claim 39, wherein said plurality of circuits are connected in series with said output amplifier stage.

43. A method for making an amplifier comprising:

connecting an output amplifier stage to an input amplifier stage; and

connecting a load stage to the output amplifier stage, the load stage comprising a plurality of circuits, each circuit comprising a capacitive component and an inductive component, and each circuit having

a resonant frequency different from a resonant frequency of the other circuits, and

a gain versus frequency curve such that all the gain versus frequency curves have, to within a tolerance, a same maximum gain value at a respective resonant frequency, and the respective gain versus frequency curves associated with two circuits having immediately adjacent resonant frequencies overlapping below a threshold at 3 dB, to within the tolerance, below the maximum gain value.

44. A method according to claim 43, wherein each circuit has a Q greater than 10;

and wherein the tolerance has an absolute value of about 1 dB.

45. A method according to claim 43, wherein the plurality of circuits are connected in series with the output amplifier stage.