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Proceedings Paper

On the suitability and development of layout templates for analog layout reuse and layout-aware synthesis
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Paper Abstract

Accelerating the synthesis of increasingly complex analog integrated circuits is key to bridge the widening gap between what we can integrate and what we can design while meeting ever-tightening time-to-market constraints. It is a well-known fact in the semiconductor industry that such goal can only be attained by means of adequate CAD methodologies, techniques, and accompanying tools. This is particularly important in analog physical synthesis (a.k.a. layout generation), where large sensitivities of the circuit performances to the many subtle details of layout implementation (device matching, loading and coupling effects, reliability, and area features are of utmost importance to analog designers), render complete automation a truly challenging task. To approach the problem, two directions have been traditionally considered, knowledge-based and optimization-based, both with their own pros and cons. Besides, recently reported solutions oriented to speed up the overall design flow by means of reuse-based practices or by cutting off time-consuming, error-prone spins between electrical and layout synthesis (a technique known as layout-aware synthesis), rely on a outstandingly rapid yet efficient layout generation method. This paper analyses the suitability of procedural layout generation based on templates (a knowledge-based approach) by examining the requirements that both layout reuse and layout-aware solutions impose, and how layout templates face them. The ability to capture the know-how of experienced layout designers and the turnaround times for layout instancing are considered main comparative aspects in relation to other layout generation approaches. A discussion on the benefit-cost trade-off of using layout templates is also included. In addition to this analysis, the paper delves deeper into systematic techniques to develop fully reusable layout templates for analog circuits, either for a change of the circuit sizing (i.e., layout retargeting) or a change of the fabrication process (i.e., layout migration). Several examples implemented with the Cadence's Virtuoso tool suite are provided as demonstration of the paper's contributions.

Paper Details

Date Published: 30 June 2005
PDF: 12 pages
Proc. SPIE 5837, VLSI Circuits and Systems II, (30 June 2005); doi: 10.1117/12.607932
Show Author Affiliations
Rafael Castro-Lopez, Instituto de Microelectronica de Sevilla, Ctr. Nacional de Microelectronica (Spain)
Francisco V. Fernandez, Instituto de Microelectronica de Sevilla, Ctr. Nacional de Microelectronica (Spain)
Angel Rodriguez Vazquez, Instituto de Microelectronica de Sevilla, Ctr. Nacional de Microelectronica (Spain)

Published in SPIE Proceedings Vol. 5837:
VLSI Circuits and Systems II
Jose Fco. Lopez; Francisco V. Fernandez; Jose Maria Lopez-Villegas; Jose M. de la Rosa, Editor(s)

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