Anasim » L*di/dt

IC Floorplanning and Power Integrity

Raj — Tue, 03 Aug 2010 20:12:09 +0000

August 2010: Early PI-aware design is a significant aspect of IC floorplanning, particularly in nanoscale systems where low power/energy and efficient use of chip/pkg metal and decoupling resources are key design constraints. The advent of 3D integration in the form of chip or package stacking makes early front-end analysis of PI through high levels of abstraction and physics-based simulations all the more necessary. Correlation between PI and thermal issues provides an added benefit in front-end PI analysis and optimization…

Continue reading in an SOCcentral featured article. More on power integrity and floorplanning: Anasim’s PI book for IC’s.

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Continuum (Analog) Analysis for Power Integrity

Raj — Sat, 12 Jun 2010 21:27:35 +0000

June 2010: Power Integrity (PI) analysis has traditionally been conducted using lumped, discrete elements and circuits, which lead to exponential simulation complexity, approximate models, and often, inaccurate results. In continuum-models based analysis, a chip power grid and distribution network is modeled as a continuous surface, employing distributed models for circuits and capacitance. This not only eliminates the exploding computational complexity for PI analysis in nanoscale chips, it facilitates physical, true-electromagnetic simulations for chips, packages, and 3D assemblies. Continuum-models based analysis is “analog” in the sense that a layer to be analyzed is treated as a spatial potential or voltage continuum, similar to analog signals being time-continuous in nature, as opposed to analyzing discrete elements and their interactions.

Read more on this in a SOCcentral featured article. A comprehensive treatment of Continuum Modeling is accessible in Anasim’s PI book for IC’s.

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Active Noise Regulation

Raj — Tue, 19 May 2009 18:29:06 +0000

“Yield loss and timing problems undetected by traditional verification and validation methods can be traced to a significant decrease in supply noise margin in components using advanced fabrication processes at and below the 90nm node. A combination of increased current density at lower supply voltages and supply pathway impedance results in large, on and off chip, relative supply variations called voltage droops. These fluctuations make it more difficult to reduce static and dynamic power and energy consumption by further reductions in supply voltage, despite the scaling direction for semiconductors…”

Read more on how active noise regulation helps minimize power and energy consumption through noise minimization here (HTML).

Grid Noise Simulation Software for Windows(tm)

Raj — Sun, 12 Apr 2009 06:26:19 +0000

RLCSim is a Windows(tm) executable that performs noise analysis on a power grid over a circuit block. This tool, a pre-cursor of pi-fp, considers grid resistance (IR drop), inductance (L*di/dt) or voltage droop, and distributed capacitance that absorbs transients, and displays noise propagation and summing within the block.

Inputs include grid parameters, block power consumption profiles and capacitance.

FREE RLCSim Windows(tm) ZIP Download

Shown below is a noise simulation result using RLCSIM demonstrating detrimental effects of lens-shaped on-chip decoupling capacitance structure. Power grid noise from an on-chip source is focused behind the capacitance structure, illustrating distributed true-electromagnetic simulation capability absent in other power integrity analysis tools.

Download a full-size version of the animation here

Effective Current Density

Prathik Raj — Sat, 11 Apr 2009 17:46:15 +0000

Download/View (PDF): Effective Current Density.pdf

Anasim Overview

Prathik Raj — Sat, 11 Apr 2009 17:07:53 +0000

Click here to download the PPT source with animations.

Anasim Power Integrity Aware Methodology

Prathik Raj — Sat, 11 Apr 2009 16:33:27 +0000

A power-integrity-aware physical design methodology enables front-end optimization of power grid metal resource usage, decoupling capacitance planning and placement, and significantly relaxes routing constraints.

Power-Integrity (PI) aware ULSI design flow

Click to enlarge image