Transistor size optimization in the tailor layout system

ABSTRACT

This paper describes a combination transistor sizing/layout compaction tool used to synthesize high performance CMOS circuits. This optimization tool is part of a large integrated layout system, called Tailor. Given any CMOS circuit layout, Tailor's transistor size optimizer will simultaneously adjust transistor sizes and compact the layout so that the minimum required area (cell pitch) for a specified upper bound on circuit delay is achieved. All delay paths are considered by modeling circuit delay with a logic independent delay graph. Tailor's optimizer globally optimizes circuit area (in one dimension) and delay by use of compaction and nonlinear programming algorithms. The optimizer does not yet optimize in two dimensions simultaneously or optimize hierarchical circuits. Results for a few optimized CMOS circuits are presented.

REFERENCES

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INDEX TERMS

Primary Classification:
  B. Hardware
  B.6 LOGIC DESIGN
      B.6.3 Design Aids
          Subjects: Optimization

Additional Classification:
  B. Hardware
  B.6 LOGIC DESIGN
      B.6.1 Design Styles
          Subjects: Combinational logic
  B.7 INTEGRATED CIRCUITS
      B.7.1 Types and Design Styles
          Subjects: VLSI (very large scale integration)
      B.7.2 Design Aids
          Subjects: Layout

  G. Mathematics of Computing
  G.1 NUMERICAL ANALYSIS
      G.1.6 Optimization
          Subjects: Nonlinear programming

General Terms:
Algorithms, Design, Performance