BGA Layout Shielding USB Signals From Source Clock Crosstalk

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Semiconductor integrated circuit devices with BGA architecture face challenges in reducing electrical crosstalk, which affects USB communication signal precision and device size, as existing shielding methods require additional terminals, complicating size reduction.

Innovation Solution

The configuration includes a ball grid array with a source clock circuit integrated between two USB interfaces, using the existing ball grids to shield the source clock signal, eliminating the need for dedicated shielding terminals and reducing crosstalk risk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional shielding terminals are added to reduce electrical crosstalk, then USB communication signal precision is improved, but device size increases

Engineering Contradiction:

ImproveUSB communication signal precisionVSAvoiddevice size

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent makes existing ball grids serve dual functions: electrical connection and signal shielding. By positioning ball grids between USB signal terminals and the source clock circuit, they simultaneously perform their primary connection function and provide electromagnetic shielding, eliminating the need for dedicated shielding terminals and preventing device size increase

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The existing ball grid array structure shields itself by utilizing its own components (the ball grids) for protection. The ball grids positioned between USB terminals and the source clock circuit automatically provide shielding for both USB signals and the clock signal without requiring external shielding structures

Inventive Principle:

Principle #25Self-service

2Quantity of substance

If terminal pitch is reduced to increase terminal density, then more USB interfaces can be accommodated, but electrical crosstalk between terminals increases

Engineering Contradiction:

Improvenumber of USB interfacesVSAvoidelectrical crosstalk

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent introduces ball grids as intermediary elements between USB signal terminals and the source clock circuit. These ball grids act as electromagnetic shields that mediate the interaction between adjacent signals, blocking crosstalk while allowing the narrow pitch arrangement to be maintained for high terminal density

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12199023B2Ball grid array for a semiconductor integrated circuit device

Publication Date: 2025.01.14 SEIKO EPSON CORP

AI summary

An electronic apparatus includes an integrated circuit board on, over, or in which a USB circuit block is provided; a first USB interface; a second USB interface; a printed circuit board on which a source clock circuit configured to output a source clock is provided; and a ball grid array that includes first, second, and third ball grids for electric coupling between the integrated circuit board and the printed circuit board. The first ball grid electrically couples the USB circuit block and the first USB interface to each other. The second ball grid electrically couples the USB circuit block and the second USB interface to each other. The third ball grid electrically couples the source clock circuit and the USB circuit block to each other. The third ball grid is located between the first ball grid and the second ball grid.