Apparatus, amplifier, system and method for receiver equalization

• US 7,548,113 B2
• Filed: 06/04/2007
• Issued: 06/16/2009
• Est. Priority Date: 06/27/2003
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Drottar, Ken
• Primary Examiner(s): Nguyen; Khanh V
• Application Number:
  US11/757,820
• Publication Number:
  US 20070247229A1
• Time in Patent Office: 743 Days
• Field of Search: 330/82, 330/253, 330/260, 330/277, 330/280, 330/291, 330/293, 330/304
• US Class Current: 330/253
• CPC Class Codes: H03F 1/086 with FET's
• CPC Class Codes: H03F 1/34 Negative-feedback-circuit arrangements with or without positive feedback H03F1/02 - H03F1/30, H03F1/38 - H03F1/50, H03F3/50 take precedence ; for rejection of common mode signals H03F3/45479
• CPC Class Codes: H03F 1/342 in field-effect transistor amplifiers
• CPC Class Codes: H03F 1/42 Modifications of amplifiers to extend the bandwidth
• CPC Class Codes: H03F 2200/36 the amplifier comprising means for increasing the bandwidth
• CPC Class Codes: H03F 3/16 with field-effect devices
• CPC Class Codes: H03F 3/45237 Complementary long tailed pairs having parallel inputs and being supplied in series
• CPC Class Codes: H03K 19/018528 with at least one differential stage

Abstract

In some embodiments an apparatus includes an amplifier, a first inverter having an input coupled to an output of the amplifier, and a second inverter having an input coupled to an output of the first inverter and an output, where the output of the second inverter is fed back to an input of the amplifier. Other embodiments are described and claimed.

Claims

1. A system comprising:

a transmitter;

a receiver; and

a transmission line coupled to the transmitter and the receiver;

the receiver including;

an amplifier; and

a delay and gain circuit coupled to an output of the amplifier, wherein

an output of the delay and gain circuit is fed back to the amplifier;

wherein the amplifier includes a first, a second and a third pMOS transistor and a first, a second and a third nMOS transistor;

wherein a gate of the first pMOS transistor and a gate of the first nMOS transistor are coupled to an input of the amplifier;

wherein a gate of the second pMOS transistor and a gate of the second nMOS transistor are coupled to a drain of the first pMOS transistor and a drain of the first nMOS transistor; and

wherein a gate of the third pMOS transistor and a gate of the third nMOS transistor are coupled to an inverse input of the amplifier.

2. The system as claimed in claim 1, wherein the receiver is a high speed serial differential receiver.

3. The system as claimed in claim 1, wherein the delay and gain circuit comprises a first inverter and a second inverter.

4. The system as claimed in claim 3, wherein the first inverter is coupled to the output of the amplifier and the first inverter and the second inverter are connected in series.

5. The system as claimed in claim 1, wherein the gate of the second pMOS transistor and the gate of the first nMOS transistor are coupled to the drain of the first pMOS transistor and the drain of the first nMOS transistor via a resistor.

6. The system as claimed in claim 3, wherein the second inverter is approximately four times the size of the first inverter.

7. The system as claimed in claim 3, wherein the first inverter is approximately one-fourth the size of the output of the amplifier.

8. The system as claimed in claim 3, wherein the first inverter is approximately one-fourth the size of the output of the amplifier and the first inverter is approximately one-fourth the size of the second inverter.

9. The system as claimed in claim 1, wherein the output of the delay and gain circuit is fed back to the amplifier as negative feedback.

10. The system as claimed in claim 1, wherein the amplifier provides positive feedback.

11. The system as claimed in claim 1, wherein the amplifier provides positive feedback and the output of the delay and gain circuit is fed back to the amplifier as negative feedback.

12. The system as claimed in claim 11, wherein the amplifier mixes the positive feedback and the negative feedback.

13. The system as claimed in claim 11, wherein the amplifier includes a resistor that mixes the positive feedback and the negative feedback.

14. The system as claimed in claim 1, wherein a gain of the feedback is a same magnitude as a loss of the transmission line.

15. The system as claimed in claim 1, wherein the output of the amplifier is coupled to the drain of the third pMOS transistor and to the drain of the third nMOS transistor.

16. The system according to claim 5, wherein the resistor has a resistance of approximately 5000 ohms.

17. The system according to claim 1, wherein a width of each of the first pMOS transistor, the second pMOS transistor and the third pMOS transistor is approximately 9.2 um, and wherein a width of the first nMOS transistor, the second nMOS transistor and the third nMOS transistor is approximately 4 um.

18. The system according to claim 1, wherein a length of each of the first pMOS transistor, the second pMOS transistor, the third pMOS transistor, the first nMOS transistor, the second nMOS transistor and the third nMOS transistor is approximately 80 nm.

19. The system according to claim 1, the amplifier further comprising a fourth pMOS transistor, a fifth pMOS transistor, a fourth nMOS transistor, and a fifth nMOS transistor.

20. The system according to claim 19, wherein a gate of the fourth pMOS transistor is coupled to a drain of the third pMOS transistor, a drain of the third nMOS transistor, and a gate of the fourth nMOS transistor, and wherein a gate of the fifth pMOS transistor is coupled to a drain of the fourth pMOS transistor, a drain of the fourth nMOS transistor, and a gate of the fifth nMOS transistor.

21. The system according to claim 20, wherein an output of the amplifier is coupled to a drain of the fifth pMOS transistor and a drain of the fifth nMOS transistor.

22. The system according to claim 21, further comprising a resistor coupled between the output of the amplifier and the gate of the second nMOS transistor.

23. The system according to claim 21, wherein the gate of the second pMOS transistor and the gate of the second nMOS transistor are coupled to the drain of the first pMOS transistor and the drain of the first nMOS transistor via a first resistor, the amplifier further comprising a second resistor coupled between the output of the amplifier and the gate of the second nMOS transistor.

24. The system as claimed in claim 1, wherein the amplifier further includes a resistor, wherein the resistor is included in a circuit that mixes positive feedback provided by the amplifier and negative feedback provided to the amplifier from the delay and gain circuit.

25. The system as claimed in claim 24, wherein the resistor is coupled to the gate of the second pMOS transistor, the gate of the second nMOS transistor, the drain of the first pMOS transistor, and the drain of the first nMOS transistor.

26. The system as claimed in claim 24, wherein the resistor is coupled to the output of the delay and gain circuit and to the gate of the second nMOS transistor.

27. The system as claimed in claim 1, wherein the output of the delay and gain circuit does not include evidence of precharging from the amplifier.

28. The system as claimed in claim 1, further comprising a resistor, wherein the gate of the second nMOS transistor and the gate of the second pMOS transistor are coupled directly together, and the drain of the first pMOS transistor and the drain of the first nMOS transistor are coupled directly together, wherein the direct coupling of the gate of the second nMOS transistor and the gate of the second pMOS transistor are coupled via the resistor to the direct coupling of the drain of the first pMOS transistor and the drain of the first nMOS transistor.

29. An apparatus comprising:

an amplifier; and

a delay and gain circuit coupled to an output of the amplifier, wherein an output of the delay and gain circuit is fed back to the amplifier;

wherein the amplifier includes a first, a second and a third pMOS transistor and a first, a second and a third nMOS transistor;

wherein a gate of the first pMOS transistor and a gate of the first nMOS transistor are coupled to an input of the amplifier;

wherein a gate of the second pMOS transistor and a gate of the second nMOS transistor are coupled to a drain of the first pMOS transistor and a drain of the first nMOS transistor; and

wherein a gate of the third pMOS transistor and a gate of the third nMOS transistor are coupled to an inverse input of the amplifier.

30. The apparatus as claimed in claim 29, wherein the delay and gain circuit comprises a first inverter and a second inverter.

31. The apparatus as claimed in claim 30, wherein the first inverter is coupled to the output of the amplifier and the first inverter and the second inverter are connected in series.

32. The apparatus as claimed in claim 29, wherein the gate of the second pMOS transistor and the gate of the second nMOS transistor are coupled to the drain of the first pMOS transistor and the drain of the first nMOS transistor via a resistor.

33. The apparatus as claimed in claim 31, wherein the second inverter is approximately four times the size of the first inverter.

34. The apparatus as claimed in claim 31, wherein the first inverter is approximately one-fourth the size of the output of the amplifier.

35. The apparatus as claimed in claim 31, wherein the first inverter is approximately one-fourth the size of the output of the amplifier and the first inverter is approximately one-fourth the size of the second inverter.

36. The apparatus as claimed in claim 29, wherein the output of the delay and gain circuit is fed back to the amplifier as negative feedback.

37. The apparatus as claimed in claim 29, wherein the amplifier provides positive feedback.

38. The apparatus as claimed in claim 29, wherein the amplifier provides positive feedback and the output of the delay and gain circuit is fed back to the amplifier as negative feedback.

39. The apparatus as claimed in claim 38, wherein the amplifier mixes the positive feedback and the negative feedback.

40. The apparatus as claimed in claim 29, wherein the amplifier includes a resistor that mixes the positive feedback and the negative feedback.

41. The apparatus as claimed in claim 29, wherein the output of the amplifier is coupled to the drain of the third pMOS transistor and to the drain of the third nMOS transistor.

42. The apparatus as claimed in claim 29, wherein the resistor has a resistance of approximately 5000 ohms.

43. The apparatus as claimed in claim 29, wherein a width of each of the first pMOS transistor, the second pMOS transistor and the third pMOS transistor is approximately 9.2 um, and wherein a width of the first nMOS transistor, the second nMOS transistor and the third nMOS transistor is approximately 4 um.

44. The apparatus as claimed in claim 29, wherein a length of each of the first pMOS transistor, the second pMOS transistor, the third pMOS transistor, the first nMOS transistor, the second nMOS transistor and the third nMOS transistor is approximately 80 nm.

45. The apparatus as claimed in claim 29, the amplifier further comprising a fourth pMOS transistor, a fifth pMOS transistor, a fourth nMOS transistor, and a fifth nMOS transistor.

46. The apparatus as claimed in claim 45, wherein a gate of the fourth pMOS transistor is coupled to a drain of the third pMOS transistor, a drain of the third nMOS transistor, and a gate of the fourth nMOS transistor, and wherein a gate of the fifth pMOS transistor is coupled to a drain of the fourth pMOS transistor, a drain of the fourth nMOS transistor, and a gate of the fifth nMOS transistor.

47. The apparatus as claimed in claim 46, wherein an output of the amplifier is coupled to a drain of the fifth pMOS transistor and a drain of the fifth nMOS transistor.

48. The apparatus as claimed in claim 47, further comprising a resistor coupled between the output of the amplifier and the gate of the second nMOS transistor.

49. The apparatus as claimed in claim 47, wherein the gate of the second pMOS transistor and the gate of the second nMOS transistor are coupled to the drain of the first pMOS transistor and the drain of the first nMOS transistor via a first resistor, the amplifier further comprising a second resistor coupled between the output of the amplifier and the gate of the second nMOS transistor.

50. The apparatus as claimed in claim 29, wherein the amplifier further includes a resistor, wherein the resistor is included in a circuit that mixes positive feedback provided by the amplifier and negative feedback provided to the amplifier from the delay and gain circuit.

51. The apparatus as claimed in claim 50, wherein the resistor is coupled to the gate of the second pMOS transistor, the gate of the second nMOS transistor, the drain of the first pMOS transistor, and the drain of the first nMOS transistor.

52. The apparatus as claimed in claim 50, wherein the resistor is coupled to the output of the delay and gain circuit and to the gate of the second nMOS transistor.

53. The system as apparatus in claim 32, wherein the output of the delay and gain circuit does not include evidence of precharging from the amplifier.

54. The apparatus as claimed in claim 32, further comprising a resistor, wherein the gate of the second nMOS transistor and the gate of the second pMOS transistor are coupled directly together, and the drain of the first pMOS transistor and the drain of the first nMOS transistor are coupled directly together, wherein the direct coupling of the gate of the second nMOS transistor and the gate of the second pMOS transistor are coupled via the resistor to the direct coupling of the drain of the first pMOS transistor and the drain of the first nMOS transistor.

55. A system comprising:

a transmitter;

a receiver; and

a transmission line coupled to the transmitter and the receiver;

the receiver including;

an amplifier;

a first inverter having an input coupled to an output of the amplifier; and

a second inverter having an input coupled to an output of the first inverter and an output, wherein the output of the second inverter is fed back to an input of the amplifier;

wherein the amplifier provides positive feedback and the output of the second inverter is fed back to the amplifier as negative feedback; and

wherein the amplifier mixes the positive feedback and the negative feedback.

56. The system as claimed in claim 55, wherein the amplifier is a CMOS amplifier.

57. The system as claimed in claim 56, wherein the CMOS amplifier is a hybrid Bazes and Chappell amplifier.

58. The system as claimed in claim 55, further comprising an output of the receiver, wherein the output does not include evidence of precharging from the amplifier.

59. The system as claimed in claim 55, wherein the receiver is a high speed serial differential receiver.

60. A system comprising:

a transmitter;

a receiver; and

a transmission line coupled to the transmitter and the receiver;

the receiver including;

an amplifier; and

a delay and gain circuit coupled to an output of the amplifier, wherein an output of the delay and gain circuit is fed back to the amplifier;

wherein the amplifier provides positive feedback and the output of the delay and gain circuit is fed back to the amplifier as negative feedback; and

wherein the amplifier mixes the positive feedback and the negative feedback.

61. The system as claimed in claim 60, wherein the amplifier includes a resistor, wherein the resistor is included in a circuit that mixes the positive feedback and the negative feedback.

62. The system as claimed in claim 60, wherein the amplifier is a CMOS amplifier.

63. The system as claimed in claim 62, wherein the CMOS amplifier is a hybrid Bazes and Chappell amplifier.

64. The system as claimed in claim 60, further comprising an output of the receiver, wherein the output does not include evidence of precharging from the amplifier.

65. The system as claimed in claim 60, wherein the receiver is a high speed serial differential receiver.