Multi-stage analog placement with various constraints

Abstract

Ahstract-In this paper, we present a placement method for analog circuit. This method can handle multiple constraints, which include multi-symmetry, proximity, signal-path clustering constraints. All these constraints are common requirement in analog circuit design. However, none of previous works considered the relations between constraints, and how to handle these multiple constraints effectively to get a convergent solution is also a seldom solved problem in previous works. Our contributions are threefold: 1) introduce signal path constraints and handle all constraints with Sequence Pair representation; 2) present a multi-stage simulated annealing strategy to acquire a faster convergence of searching process; 3) first introduce a post refinement stage to further improve the result placement, using linear programming. The effectiveness and efficiency of experimental results are promising.

Common-Centroid FinFET Placement Considering the Impact of Gate Misalignment

“…To generate a matched layout of the transistors in a current mirror or a differential pair, all the previous works [13,14,16,18,19,26,27,28] simply followed the general common-centroid rules, including coincidence, symmetry, dispersion, and compactness [6]. None of them considered the impact of gate misalignment arising from the FinFET technology.…”

SWARM: A Self-Organization Approach for Layout Automation in Analog IC Design

“…Amongst others, particular attention lies on abstract floorplan models such as TCG-S [4], sequence pairs [5], [9] and [10] and more enhanced representations [11]. Particular research effort is spent on the formal, explicit consideration of constraints.…”

“…Particular research effort is spent on the formal, explicit consideration of constraints. E.g., for placement many algorithms take device symmetry [5] and [11] and device proximity [10] and [14] into account. For routing, the constraints of interest include net shielding [6] and wiring symmetry [8].…”