Cross-point switch fabric and switch fabric slice

1. A cross-point switch fabric slice comprising:

a multistage gated buffer tree comprising at least first and second serially connected gated buffer stages; and

N inputs coupled to preselected gated buffers in the first gated buffer stage,

wherein the preselected gated buffers include control inputs for receiving gated buffer stage control signals, and

wherein the multistage gated buffer tree provides a signal path from any of the N inputs to at least one switch output in response to the gated buffer stage control signals.

2. The cross-point switch fabric slice of claim 1 , wherein each of the N inputs comprises a differential input.

3. The cross-point switch fabric slice of claim 1 , wherein the multistage gated buffer tree comprises at least first, second, and third serially connected gated buffer stages.

4. The cross-point switch fabric slice of claim 3 , wherein preselected gated buffers of the second and third gated buffer stages include control inputs for receiving the gated buffer stage control signals, wherein the multistage gated buffer tree provides a signal path from any of the N inputs to the third gated buffer stage switch output in response to the gated buffer stage control signals.

5. The cross-point switch fabric slice of claim 3 , wherein the multistage gated buffer tree is an N-to-1 multistage gated buffer tree.

6. The cross-point switch fabric slice of claim 1 , wherein the multistage gated buffer tree is an N-to-1 multistage gated buffer tree.

7. The cross-point switch fabric slice of claim 1 , wherein the gated buffers in the second gated buffer stage are characterized by greater drive capability than the gated buffers in the first gated buffer stage.

8. The cross-point switch fabric slice of claim 1 , wherein each of the preselected gated buffers in the first gated buffer stage includes a differential input, a differential output, and a predetermined number of gated buffer stage control signal inputs.

9. The cross-point switch fabric slice of claim 8 , wherein the differential input is connected through to the differential output when all the predetermined number of gated buffer stage control signal inputs are active.

10. The cross-point switch fabric slice of claim 1 , wherein each of preselected gated buffers in the second gated buffer stage includes a differential input, a differential output, and a predetermined number of gated buffer stage control signal inputs.

11. The cross-point switch fabric slice of claim 10 , wherein the differential input is connected through to the differential output when all the predetermined number of gated buffer stage control signal inputs are active.

12. A cross-point switch fabric slice comprising:

a multistage gated buffer tree comprising at least first, second and third serially connected gated buffer stages, wherein the gated buffers in the second gated buffer stage are characterized by greater drive capability than the gated buffers in the first gated buffer stage, and wherein the gated buffers in the third gated buffer stage are characterized by greater drive capability than the gated buffers in the second gated buffer stage; and

N inputs coupled to preselected gated buffers in the first gated buffer stage,

wherein the gated buffers of the first, second and third gated buffer stages include control inputs for receiving gated buffer stage control signals, and

wherein the multistage gated buffer tree provides a signal path from any of the N inputs to at least one switch output in response to the gated buffer stage control signals.

13. The cross-point switch fabric slice of claim 12 , wherein the gated buffers in the first, second and third gated buffer stages include a differential input, a differential output, and a predetermined number of gated buffer stage control signal inputs.

14. A cross-point switch fabric slice comprising:

a multistage gated buffer tree comprising at least first and second serially connected gated buffer stages; and

N inputs coupled to preselected gated buffers in the first gated buffer stage,

wherein the preselected gated buffers include control inputs for receiving gated buffer stage control signals,

wherein the multistage gated buffer tree provides a signal path from any of the N inputs to at least one switch output in response to the gated buffer stage control signals; and

wherein the first gated buffer stage is partitioned into a first substage and a second substage, and wherein at least one of the gated buffer stage control signals is shared between the first substage and the second substage.

15. The cross-point switch fabric slice of claim 14 , wherein a first gated buffer stage control signal activates a first gated buffer in the first substage, and wherein the first gated buffer stage control signal activates a corresponding gated buffer in the second substage.

16. A cross-point switch fabric comprising:

N inputs;

a first cross-point switch fabric slice comprising:

a first multistage gated buffer tree coupled to the N inputs and comprising a first gated buffer stage coupled to the N inputs and a second gated buffer stage serially connected with the first gated buffer stage;

wherein the first multistage gated buffer tree provides a signal path from any of the N inputs to a first switch output in response to first gated buffer stage control signals; and

a second cross-point switch fabric slice comprising:

a second multistage gated buffer tree coupled to the N inputs and comprising a third gated buffer stage coupled to the N inputs and a fourth gated buffer stage serially connected with the third gated buffer stage;

wherein the second multistage gated buffer tree provides a signal path from any of the N inputs to a second switch output in response to second gated buffer stage control signals.

17. The cross-point switch fabric of claim 16 , further comprising at least one additional multistage gated buffer tree cross-point switch fabric slice coupled to the N inputs, and at least one additional switch output.

18. The cross-point switch fabric of claim 16 , wherein gated buffers in the second gated buffer stage are characterized by greater drive capability than gated buffers in the first gated buffer stage.

19. The cross-point switch fabric of claim 16 , wherein the second gated buffer stage comprises fewer gated buffers than the first gated buffer stage.

20. The cross-point switch fabric of claim 16 , wherein the gated buffers in the fourth gated buffer stage are characterized by greater drive capability than the gated buffers in the third gated buffer stage.

21. The cross-point switch fabric of claim 16 , wherein the fourth gated buffer stage comprises fewer gated buffers than the third gated buffer stage.

22. A cross-point switch fabric comprising:

N inputs;

a first cross-point switch fabric slice comprising:

a first multistage gated buffer tree coupled to the N inputs and comprising a first gated buffer stage coupled to the N inputs and a second gated buffer stage serially connected with the first gated buffer stage;

wherein the first multistage gated buffer tree provides a signal path from any of the N inputs to a first switch output in response to first gated buffer stage control signals; and

a second cross-point switch fabric slice comprising:

a second multistage gated buffer tree coupled to the N inputs and comprising a third gated buffer stage coupled to the N inputs and a fourth gated buffer stage serially connected with the third gated buffer stage;

wherein the second multistage gated buffer tree provides a signal path from any of the N inputs to a second switch output in response to second gated buffer stage control signals; and

wherein at least one of the first and second multistage gated buffer trees comprises an additional gated buffer stage serially connected with one of the second gated buffer stages.

23. The cross-point switch fabric of claim 22 , wherein the gated buffers in the additional gated buffer stage are characterized by greater drive capability than the serially connected gated buffers in the second gated buffer stage.

24. The cross-point switch fabric of claim 22 , wherein the gated buffers in the additional gated buffer stage are fewer in number than the serially connected gated buffers in the second gated buffer stage.

25. The cross-point switch fabric of claim 16 , configured as an N×N switch further comprising at least one additional multistage gated buffer tree cross-point switch fabric slice coupled to the N inputs, and at least one additional switch output.

26. The cross-point switch fabric of claim 16 , wherein at least one of the first and third gated buffer stages is partitioned into a first substage and a second substage, and wherein gated buffer stage control signals are shared between the first substage and the second substage.

27. The cross-point switch fabric of claim 26 , wherein a first gated buffer stage control signal activates a first gated buffer in the first substage, and wherein the first gated buffer stage control signal activates a corresponding gated buffer in the second substage.

28. A method for routing a signal through a cross-point switch fabric, the method comprising:

applying a signal on one of N inputs;

activating a signal path through a first multistage gated buffer tree comprising at least first and second serially connected gated buffer stages, wherein the activating of the signal path includes multistage decoding, wherein the multistage decoding includes applying a first gated buffer stage control signal to control inputs of corresponding gated buffers in both a first and a second substage of the first gated buffer stage; and

outputting the signal on a switch output coupled to the multistage gated buffer tree.

29. The method of claim 28 , wherein activating further comprises activating a signal path through one of a plurality of multistage gated buffer trees.

30. The method of claim 29 , wherein outputting comprises outputting the signal on one of M switch outputs provided by the plurality of multistage gated buffer trees.

31. The method of claim 30 , wherein N=M.

32. The method of claim 28 , further comprising providing increased drive capability in the second gated buffer stage over the first gated buffer stage.

33. A method for routing a signal through a cross-point switch fabric, the method comprising:

applying a signal on one of N inputs;

activating a signal path through a first multistage gated buffer tree comprising at least first and second serially connected gated buffer stages; and

outputting the signal on a switch output coupled to the multistage gated buffer tree,

wherein activating comprises multistage decoding,

wherein multistage decoding comprises activating, using a first gated buffer stage control signal, corresponding gated buffers in both a first and a second substage of the first gated buffer stage, and

wherein multistage decoding further comprises activating, using a second gated buffer stage control signal, a gated buffer in the second gated buffer stage to select one activated gated buffer in the first gated buffer stage.