Analyzing substrate noise

• US 7,246,335 B2
• Filed: 02/15/2005
• Issued: 07/17/2007
• Est. Priority Date: 02/15/2005
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Horie, Takeshi, Tahoori, Mehdi B., Miyoshi, Takashi, Murgai, Rajeev, Reddy, Subodh M.
• Primary Examiner(s): Dinh; Paul
• Assistant Examiner(s): Doan; Nghia M.
• Application Number:
  US11/058,900
• Publication Number:
  US 20060184904A1
• Time in Patent Office: 882 Days
• Field of Search: 716 1- 21, 703 14- 23
• US Class Current: 716/113
• CPC Class Codes: G06F 30/367 Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods

Abstract

In one embodiment, a method for analyzing substrate noise includes applying a static timing analysis (STA) algorithm to a description of a digital circuit. Application of the STA algorithm generates timing information on one or more gates in the digital circuit. The method also includes applying a current waveform generation (CWG) algorithm to the description of the digital circuit, the timing information on one or more gates in the digital circuit, and a description of switching activity in the digital circuit. Application of the CWG algorithm generates a current waveform. The method also includes generating a reduced model (RM) of the digital circuit for simulation according to the description of the digital circuit, the current waveform, and a model of a package associated with the digital circuit. Simulation of the RM of the digital circuit generates an indication of noise in a substrate associated with the digital circuit.

Claims

1. A system for analyzing substrate noise (SN), the system comprising:

a static timing analysis (STA) module operable to apply an STA algorithm to a description of a digital circuit, application of the STA algorithm generating timing information on one or more gates in the digital circuit;

a current waveform generator operable to apply a current waveform generation (CWG) algorithm to the description of the digital circuit, the timing information on one or more gates in the digital circuit, and a description of switching activity in the digital circuit, application of the CWG algorithm generating a current waveform; and

a reduced model (RM) generator operable to generate an RM of the digital circuit for simulation, the RM generator generating the RM of the digital circuit according to the description of the digital circuit, the current waveform, and a model of a package associated with the digital circuit, simulation of the RM of the digital circuit generating an indication of noise in a substrate associated with the digital circuit.

2. The system of claim 1, wherein the timing information comprises worst-case timing in the digital circuit over a plurality of input patterns to the digital circuit.

3. The system of claim 2, wherein the timing information comprises worst-case timing in the digital circuit over all possible input patterns to the digital circuit.

4. The system of claim 1, wherein the CWG algorithm comprises an overlapping algorithm operable to generate one or more maximum peak currents of one or more gates in the digital circuit in one or more time windows.

5. The system of claim 1, wherein the RM comprises only passive elements.

6. The system of claim 1, wherein the RM comprises only a few elements.

7. The system of claim 1, wherein the RM derives from a sensitivity analysis.

8. The system of claim 1, wherein the RM is independent of input pattern to the digital circuit.

9. The system of claim 1, wherein the indication of noise in the substrate comprises a peak-to-peak value.

10. The system of claim 9, wherein the indication of noise comprises a maximum peak-to-peak value.

11. The system of claim 1, wherein the substrate is associated with analog circuitry in addition to being associated with the digital circuit.

12. A method for analyzing substrate noise (SN), the method comprising:

applying a static timing analysis (STA) algorithm to a description of a digital circuit, application of the STA algorithm generating timing information on one or more gates in the digital circuit;

applying a current waveform generation (CWG) algorithm to the description of the digital circuit, the timing information on one or more gates in the digital circuit, and a description of switching activity in the digital circuit, application of the CWG algorithm generating a current waveform; and

generating a reduced model (RM) of the digital circuit for simulation according to the description of the digital circuit, the current waveform, and a model of a package associated with the digital circuit, simulation of the RM of the digital circuit generating an indication of noise in a substrate associated with the digital circuit.

13. The method of claim 12, wherein the timing information comprises worst-case timing in the digital circuit over a plurality of input patterns to the digital circuit.

14. The method of claim 13, wherein the timing information comprises worst-case timing in the digital circuit over all possible input patterns to the digital circuit.

15. The method of claim 12, wherein the CWG algorithm comprises an overlapping algorithm operable to generate one or more maximum peak currents of one or more gates in the digital circuit in one or more time windows.

16. The method of claim 12, wherein the RM comprises only passive elements.

17. The method of claim 12, wherein the RM comprises only a few elements.

18. The method of claim 12, wherein the RM derives from a sensitivity analysis.

19. The method of claim 12, wherein the RM is independent of input pattern to the digital circuit.

20. The method of claim 12, wherein the indication of noise in the substrate comprises a peak-to-peak value.

21. The method of claim 20, wherein the indication of noise comprises a maximum peak-to-peak value.

22. The method of claim 12, wherein the substrate is associated with analog circuitry in addition to being associated with the digital circuit.

23. Software for analyzing substrate noise (SN), the software encoded in a computer-readable medium and when executed operable to:

apply a static timing analysis (STA) algorithm to a description of a digital circuit, application of the STA algorithm generating timing information on one or more gates in the digital circuit;

apply a current waveform generation (CWG) algorithm to the description of the digital circuit, the timing information on one or more gates in the digital circuit, and a description of switching activity in the digital circuit, application of the CWG algorithm generating a current waveform; and

generate a reduced model (RM) of the digital circuit for simulation according to the description of the digital circuit, the current waveform, and a model of a package associated with the digital circuit, simulation of the RM of the digital circuit generating an indication of noise in a substrate associated with the digital circuit.

24. The software of claim 23, wherein the timing information comprises worst-case timing in the digital circuit over a plurality of input patterns to the digital circuit.

25. The software of claim 24, wherein the timing information comprises worst-case timing in the digital circuit over all possible input patterns to the digital circuit.

26. The software of claim 23, wherein the CWG algorithm comprises an overlapping algorithm operable to generate one or more maximum peak currents of one or more gates in the digital circuit in one or more time windows.

27. The software of claim 23, wherein the RM comprises only passive elements.

28. The software of claim 23, wherein the RM comprises only a few elements.

29. The software of claim 23, wherein the RM derives from a sensitivity analysis.

30. The software of claim 23, wherein the RM is independent of input pattern to the digital circuit.

31. The software of claim 23, wherein the indication of noise in the substrate comprises a peak-to-peak value.

32. The software of claim 31, wherein the indication of noise comprises a maximum peak-to-peak value.

33. The software of claim 23, wherein the substrate is associated with analog circuitry in addition to being associated with the digital circuit.

34. A system for analyzing substrate noise (SN), the system comprising:

means for applying a static timing analysis (STA) algorithm to a description of a digital circuit, application of the STA algorithm generating timing information on one or more gates in the digital circuit;

means for applying a current waveform generation (CWG) algorithm to the description of the digital circuit, the timing information on one or more gates in the digital circuit, and a description of switching activity in the digital circuit, application of the CWG algorithm generating a current waveform; and

means for generating a reduced model (RM) of the digital circuit for simulation according to the description of the digital circuit, the current waveform, and a model of a package associated with the digital circuit, simulation of the RM of the digital circuit generating an indication of noise in a substrate associated with the digital circuit.