Analog standard cells for A-D and D-A converters with Δ-∑ modulators

Takao Kaneko*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


An analog standard cell layout configuration is proposed for simplifying the design and reducing the man-hours for designing mixed analog-digital LSIs, and analog standard cells are fabricated for A-D and D-A converters with Δ-∑ modulators. This works seeks to implement 2-D cell placement with up-down and left-right mirror rotation and shorter high-impedance analog wiring than conventional 1-D placement in order to obtain high-performance analog characteristics. By considering sensitivity to noise, routing channels have been classified into 4 types: high-impedance analog, low-impedance analog, analog-digital, and digital, and efforts have been made to prevent analog wires from crossing over digital wires. In addition to power and analog ground wires, analog standard cells have built-in analog ground wires with attached wells optimized for shielding. These wires are interconnected to a new isolation cell that separates analog circuits from digital circuits and routing channels. Based on the above layout structure, 46 different types of analog standard cells have been designed. Also, the analog part of Δ-∑ type A-D and D-A converters can be automatically designed in conjunction with interactive processing and chips fabricated by using these cells. It was found that, compared to manual design, one could easily obtain a chip occupying less than 1.5-times the area with about 2/3 the man-days using this approach. In comparison with manual design, it was also found that the S/N ratio could be reduced from about 6 to 7 dB.

Original languageEnglish
Pages (from-to)252-260
Number of pages9
JournalIEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences
Issue number2
Publication statusPublished - 2000
Externally publishedYes


  • Analog layout
  • Mixed analog-digital LSI
  • Standard cell
  • Δ-∑ type A-D converter
  • Δ-∑ type D-A converter

ASJC Scopus subject areas

  • Signal Processing
  • Computer Graphics and Computer-Aided Design
  • Electrical and Electronic Engineering
  • Applied Mathematics


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