Staggered I/O Groups for IC Pad Pitch and Supply Stability

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Solution Overview

Problem

Conventional I/O architectures face challenges in optimizing the pitch and density of signal and supply pads on integrated circuits, balancing signal pad density with stable voltage supply without increasing complexity or reducing the number of supply pads.

Innovation Solution

The proposed solution involves grouping multiple signal pads and supply pads into a single layout cell, allowing for staggered or aligned arrangements, which reduces the effective pitch while maintaining adequate supply stability by integrating driver circuits and ESD protection within these group layout cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional inline I/O scheme is used, then supply stability is maintained with adequate spacing, but effective pitch per signal pad increases to 54.8 um

Engineering Contradiction:

Improvesupply stabilityVSAvoideffective pitch per signal pad

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent combines multiple signal pads and supply pads into a single group layout cell, merging previously separate I/O cells into an integrated structure that achieves both compact pitch and adequate supply stability

Inventive Principle:

Principle #5Merging (Combining)

2Length of moving object

If conventional staggered I/O scheme is used, then pitch is reduced to 35 um, but supply stability may be compromised with fewer supply pads per signal pad

Engineering Contradiction:

ImprovepitchVSAvoidsupply stability

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The patent applies different spacing configurations within the group layout cell, allowing adjacent pads to have different pitch values (Pa and Pb) to optimize both compactness and supply stability in different local regions of the I/O structure

Inventive Principle:

Principle #3Local quality

3Reliability

If PGE I/O scheme is used, then supply pads per signal pad increases to 1:1 ratio, but effective pitch worsens and fewer I/Os fit around chip perimeter

Engineering Contradiction:

Improvesupply stabilityVSAvoidnumber of I/Os per chip perimeter

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The group layout cell serves multiple functions simultaneously: it provides signal I/O pads, supply pads, driver circuitry, and ESD protection in a single integrated structure, maximizing the utility of each cell while maintaining compact pitch

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Reliability

If separate power-supply cells are required for each signal pad, then supply stability is maintained, but device complexity and area increase

Engineering Contradiction:

Improvesupply stabilityVSAvoidnumber of separate cells

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple previously separate I/O cells (signal pads and power-supply pads) into a single group layout cell, reducing overall device complexity while maintaining adequate supply stability through integrated design

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS7932744B1Staggered I/O groups for integrated circuits

Publication Date: 2011.04.26 MICROSEMI SOC CORP

AI summary

An I/O scheme for an integrated circuit includes a group layout cell. The group layout cell includes a plurality of signal I/O pads. A driver circuit is coupled to each signal I/O pad. The group layout cell also includes two I/O driver-circuit power-supply pads. ESD protection circuitry is coupled to the plurality of driver circuits. The signal I/O pads and the I/O driver-circuit power-supply pads are arranged in rows. The rows may be regular or staggered.