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Title: US6205571: X-Y grid tree tuning method
[ Derwent Title ]


Country: US United States of America

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20 pages

 
Inventor: Camporese, Peter J.; Hopewell Junction, NY
Deutsch, Alina; Chappagua, NY
McNamara, Timothy Gerard; Fishkill, NY
Restle, Phillip John; Katonah, NY
Webber, David Allan; Poughkeepsie, NY

Assignee: International Business Machines Corporation, Armonk, NY
other patents from INTERNATIONAL BUSINESS MACHINES CORPORATION (280070) (approx. 44,393)
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Published / Filed: 2001-03-20 / 1998-12-29

Application Number: US1998000222143

IPC Code: Advanced: G06F 1/10; G06F 17/50;
Core: more...
IPC-7: G06F 17/50;

ECLA Code: G06F1/10; G06F17/50L2;

U.S. Class: Current: 716/114; 716/115; 716/133; 716/134;
Original: 716/002; 716/014;

Field of Search: 395/500.15 716/002,14

Priority Number:
1998-12-29  US1998000222143

Abstract: An X-Y grid tree clock distribution network for distributing a clock signal across a VLSI chip. Tunable wiring tree networks are combined with an X-Y grid vertically and horizontally connecting all the tree end points. No drivers are necessary at connection points of the tree end points to the X-Y grid. The final X-Y grid distributes the clock signal close to every place it is needed, and reduces skew across local regions. A tuning method allows buffering of the clock signal, while minimizing both nominal clock skew and clock uncertainty. The tuned tree networks provide low skew even with variations in clock load density and non-ideal buffer placement, while minimizing the number of buffers needed. The tuning method first represents a total capacitance of one or more of clock pin loads and twig wiring as a clustered grid load. Next, a smoothing of the clustered grid loads approximates the effect of the X-Y grid. Electrical simulation models are created for network components and clustered grid loads are substituted with smoothed clustered grid loads. A set of NSECTOR electrical net lists are next created by extracting a net list with associated X-Y grid wires cut to isolate each sector net list from its neighboring sectors. Each NSECTOR electrical net list is then tuned, wherein the smoothed clustered grid loads represent an approximation of the effects of the neighboring sectors of each NSECTOR electrical net list.

Attorney, Agent or Firm: Jordan, Kevin M. ; Ellenbogen, Wayne L. ;

Primary / Asst. Examiners: Swann, Tod R.; Jones, Hugh

Maintenance Status: E2 Expired  Check current status

INPADOC Legal Status: Show legal status actions

Parent Case:

CROSS-REFERENCE TO RELATED APPLICATIONS
    The present invention is related to co-pending U.S. patent application Ser. No. 09/022,141, entitled "X-Y Grid Tree Clock Distribution Network with Tunable Tree and Grid Networks," by Restle et al., filed of even date herewith. This co-pending application and the present invention are commonly assigned to the International Business Machines Corporation, Armonk, N.Y. This co-pending application is hereby incorporated by reference in its entirety into the present application.

Family: None

First Claim:
Show all 18 claims
What is claimed is:     1. A method for tuning a X-Y grid tree clock distribution network, the method comprising the steps of:
  • clustering a total capacitance of one or more of pins and wiring as a clustered grid load;
  • smoothing clustered grid loads to approximate the effect of the X-Y grid;
  • creating electrical simulation models for network components and substituting clustered grid loads with smoothed clustered grid loads; and
  • creating a set of NSECTOR electrical net lists by extracting a net list with associated X-Y grid wires cut to isolate each sector net list from neighboring sectors; and
  • tuning each electrical net list as a function of the smoothed clustered grid loads to reduce one or more of power; wiring; and skew; wherein the smoothed clustered grid loads represent an approximation of the effects of the neighboring sectors of said each NSECTOR electrical net list.


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Description: Show description

Forward References: Show 36 U.S. patent(s) that reference this one

       
U.S. References: Go to Result Set: All U.S. references   |  Forward references (36)   |   Backward references (2)   |   Citation Link

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PDF
Patent  Pub.Date  Inventor Assignee   Title
Get PDF - 8pp US5656963  1997-08 Masleid et al.  International Business Machines Corporation Clock distribution network for reducing clock skew
Get PDF - 17pp US6006025  1999-12 Cook et al.  International Business Machines Corporation Method of clock routing for semiconductor chips
       
Foreign References: None

Other References:
  • C. L. Ratzlaff et al., "RICE: Rapid Interconnect Circuit Evaluation Using AWE," IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, vol. 13, No. 6, Jun. 1994, pp. 763-776. (14 pages) Cited by 10 patents [ISI abstract]
  • P. J. Restle et al., "Measurement and Modeling of On-Chip Transmission Line Effects in a 400 MHz Microprocessor," IEEE Journal of Solid-State Circuits, vol. 33, No. 4, Apr. 1998, pp. 662-665. (4 pages) Cited by 4 patents [ISI abstract]


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