A Charge Flow Formulation for Guiding Analog/Mixed-Signal Placement

Tonmoy Dhar, Ramprasath S, Jitesh Poojary, Soner Yaldiz, Steven Burns, Ramesh Harjani, Sachin S. Sapatnekar

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

An analog/mixed-signal designer typically performs circuit optimization, involving intensive SPICE simulations, on a schematic netlist and then sends the optimized netlist to layout. During the layout phase, it is vital to maintain symmetry requirements to avoid performance degradation due to mismatch: these constraints are usually specified using user input or by invoking an external tool. Moreover, to achieve high performance, the layout must avoid large interconnect parasitics on critical nets. Prior works that optimize parasitics during placement work with coarse metrics such as the half-perimeter wire length, but these metrics do not appropriately emphasize performance-critical nets. The novel charge flow (CF) formulation in this work addresses both symmetry detection and parasitic optimization. By leveraging schematic-level simulations, which are available 'for free' from the circuit optimization step, the approach (a) alters the objective function to emphasize the reduction of parasitics on performance-critical nets, and (b) identifies symmetric elements/element groups. The effectiveness of the CF-based approach is demonstrated on a variety of circuits within a stochastic placement engine.

Original languageEnglish (US)
Title of host publicationProceedings of the 2022 Design, Automation and Test in Europe Conference and Exhibition, DATE 2022
EditorsCristiana Bolchini, Ingrid Verbauwhede, Ioana Vatajelu
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages148-153
Number of pages6
ISBN (Electronic)9783981926361
DOIs
StatePublished - 2022
Event2022 Design, Automation and Test in Europe Conference and Exhibition, DATE 2022 - Virtual, Online, Belgium
Duration: Mar 14 2022Mar 23 2022

Publication series

NameProceedings of the 2022 Design, Automation and Test in Europe Conference and Exhibition, DATE 2022

Conference

Conference2022 Design, Automation and Test in Europe Conference and Exhibition, DATE 2022
Country/TerritoryBelgium
CityVirtual, Online
Period3/14/223/23/22

Bibliographical note

Funding Information:
This work is supported in part by the DARPA IDEA program, as part of the ALIGN project, under SPAWAR Contract N660011824048.

Publisher Copyright:
© 2022 EDAA.

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