Multi-Chip Clock Sharing Layout for Low-Jitter Synchronization
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Solution Overview
Problem
High-capacity devices with multi-chip architectures face challenges in distributing clock signals with minimal variation, as existing methods like ultra-short-reach serializer-deserializer circuits are expensive and alternatives like JTAG or MDIO are limited to configuration and debugging, while parallel interfaces support only lower speeds, contributing to clock jitter.
Innovation Solution
The implementation of integrated circuit devices with clock generators and conductors on a common substrate, where clock terminals on each chip are connected via upper-layer metallizations to minimize clock jitter, allowing each chip to be clocked independently or synchronized by a shared clock source, enabling efficient clock signal distribution across multiple chips in a multi-chip module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If ultra-short-reach high-speed serializer-deserializer circuits are used to distribute clock signals, then clock signal distribution speed is improved, but power consumption and device area increase significantly
Solution Approach 1:
The system segments the clock distribution function by providing each chip with its own clock generator and dedicated clock conductors, eliminating the need for complex serializer-deserializer circuits while maintaining high-speed performance and reducing power consumption per chip
Solution Approach 2:
Each chip contains a copy of the clock generator circuitry, allowing independent clock signal generation without requiring expensive high-speed serialization infrastructure, thereby reducing both power consumption and device area while maintaining high-speed operation
2Speed
If ultra-short-reach high-speed serializer-deserializer circuits are used to distribute clock signals, then clock signal distribution speed is improved, but device area increases significantly
Solution Approach 1:
The clock distribution function is segmented across individual chips, each with its own clock generator and dedicated conductors, eliminating the need for large-area serializer-deserializer circuits and reducing overall device area while maintaining high-speed performance
Solution Approach 2:
By copying the clock generator functionality to each chip rather than using centralized high-speed serialization infrastructure, the device area is significantly reduced while maintaining high-speed clock signal distribution capability
3Use of energy by moving object
If lower-speed serial interfaces like JTAG or MDIO are used for clock distribution, then power consumption and device area are reduced, but clock jitter increases and they are limited to configuration and debugging
Solution Approach 1:
The system segments the clock signal path with dedicated clock conductors for each chip, isolating clock signals from data signals and reducing jitter while maintaining low power consumption, enabling reliable high-speed operation beyond just configuration and debugging
Solution Approach 2:
Each chip has its own clock generator copy, ensuring stable clock signals without relying on lower-speed serial interfaces, thereby achieving both low power consumption and high reliability for production operation at high speeds
4Area of stationary object
If parallel interfaces are used for clock distribution, then device area is reduced, but supported speed is limited to lower speeds
Solution Approach 1:
The system uses segmented dedicated clock conductors for each chip rather than shared parallel interfaces, enabling high-speed operation while maintaining compact device area through direct point-to-point connections
Solution Approach 2:
By copying the clock generation capability to each chip and using dedicated conductors, the system achieves high-speed performance without requiring large-area parallel interface infrastructure, breaking the speed-area tradeoff
Data Source
AI summary
An integrated circuit device includes a plurality of integrated circuit chips located on a common substrate, each respective integrated circuit chip from among the plurality of integrated circuit chips including functional circuitry, a clock generator, clock circuitry including clock terminals at an edge of the respective integrated circuit chip, initial clock conductors configured to conduct a clock signal output by the clock generator from the clock generator to the clock terminals, and functional clock conductors configured to conduct the clock signal from the clock terminals to the functional circuitry. Each respective chip is located on the common substrate in an orientation that exposes the clock terminals on the respective chip to face corresponding clock terminals on at least one other chip among the plurality of integrated circuit chips, configured for interconnection of the plurality of integrated circuit chips into a multi-chip module with a common clock.