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[Author] Xiaoke ZHU(2hit)

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  • A Fast Algorithm for Crosspoint Assignment under Crosstalk Constraints with Shielding Effects

    Keiji KIDA  Xiaoke ZHU  Changwen ZHUANG  Yasuhiro TAKASHIMA  Shigetoshi NAKATAKE  

     
    PAPER-Physical Design

      Vol:
    E87-A No:12
      Page(s):
    3258-3264

    This paper presents a novel algorithm for crosspoint assignment (CPA) that takes into consideration crosstalk noise and shielding effects in deep sub-micron design. We introduce a conditional constraint which is imposed on a sensitive net-pair to detach one net from the other or to put another insensitive net between them for shielding. We provide two algorithms which can handle the conditional constraint: One is based on an ILP, which outputs an exact optimum solution. The other is a fast heuristics whose time complexity is O(n2 log n), where n is the number of pins. In experiments, we tested these algorithms for industrial examples. The results showed that the conditional constraint for shielding released algorithms from a tight space of feasible assignments. Our heuristics ran quickly and attained near optimum solutions.

  • A Device-Level Placement with Schema Based Clusters in Analog IC Layouts

    Takashi NOJIMA  Xiaoke ZHU  Yasuhiro TAKASHIMA  Shigetoshi NAKATAKE  Yoji KAJITANI  

     
    PAPER-Analog Layout

      Vol:
    E87-A No:12
      Page(s):
    3301-3308

    A challenge to an automated layout of analog ICs starts with the insight into high quality placements crafted by experts. We observe first that matched devices or elemental functions such as input, output, amplifiers, etc are clustered. Second, devices in the same cluster are located faithfully to the drawn schema. Third, these two features are simultaneously fulfilled in a well-compacted placement. This paper proposes a novel device-level placement that simulates the above features based on Sequence-Pair. A slight modification of the meaning, say, of relation "A is left-of B" to relation "A is not right-of B" enlarges the freedom and allows a neater compaction of clusters allowing zigzag border curves. As the consequence, clusters are placed faithfully to relative position in the schema. We tested our algorithm for industrial instances and compared results with those by manual design. The results showed better features in performance figures than the those of manual designs by, on average, 13.5% and 21.2% with respect to the area and total net-length.