Multi-Die Transceiver Clock Sharing Circuit
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Solution Overview
Problem
In multi-port or multi-lane networking devices, such as Ethernet switches or physical layer transceivers, clock skew between lanes can be significant due to process variations when dies from different wafers or areas of the same wafer are used.
Innovation Solution
A multi-lane integrated circuit transceiver device is designed with digital clock distribution circuitry that shares a digital clock signal from one receive block across two integrated circuit dies, using buffer circuitry on each die to distribute the clock as a baseline for digital clock generation in transmit blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dies from different wafers or areas are used to spread ports or lanes across multiple dies, then device capacity and functionality are improved, but clock skew between lanes increases due to process variations
Solution Approach 1:
The patent divides the clock distribution system into multiple independent clock trees, each serving a specific die or group of dies. Each clock tree is independently calibrated to compensate for process variations, allowing the system to maintain precise clock timing across multiple dies while supporting high device capacity.
Solution Approach 2:
The patent implements local clock calibration where each die or clock tree has its own calibration parameters stored in non-volatile memory. This allows each local clock distribution network to be independently optimized for its specific process variations, minimizing clock skew locally while maintaining overall system consistency.
2Adaptability or versatility
If separate clock generation circuitry is implemented in each transmit block, then clock independence and flexibility are improved, but power consumption and device complexity increase
Solution Approach 1:
The patent merges clock generation resources by implementing shared clock trees that serve multiple transmit blocks. Instead of each transmit block having completely independent clock generation, the system uses shared clock distribution networks with local calibration capabilities, reducing overall power consumption while maintaining the flexibility and independence needed for precise clock timing.
Solution Approach 2:
The patent creates universal clock distribution infrastructure that can serve multiple functions: providing clock signals to multiple transmit blocks, supporting both intra-die and inter-die clock distribution, and enabling dynamic calibration. This multi-functional approach reduces the need for separate dedicated clock generation circuitry in each transmit block.
3Use of energy by moving object
If digital clock distribution circuitry is used to share clock signals across dies, then power consumption is reduced, but clock signal integrity and timing precision may be compromised
Solution Approach 1:
The patent introduces calibration data stored in non-volatile memory as an intermediary between the digital clock distribution circuitry and the clock signal generation. This calibration data compensates for process variations and timing skew introduced by digital distribution, allowing the system to maintain clock signal integrity while using power-efficient digital distribution methods.
Solution Approach 2:
The patent implements a calibration process where clock timing characteristics are measured and stored in non-volatile memory. This feedback mechanism allows the system to compensate for timing variations in the digital clock distribution network, maintaining signal integrity while benefiting from the power efficiency of digital distribution.
Data Source
AI summary
A multi-lane integrated circuit transceiver device includes first and second integrated circuit dies having respective first and second pluralities of transmit block/receive block pairs. Each respective transmit block and each respective receive block in the first plurality of block pairs on the first die and the second plurality of block pairs on the second die includes respective digital clock generation circuitry. The device further includes digital clock distribution circuitry to distribute a digital clock signal output by one respective receive block, in one of the first and second pluralities of block pairs, to the transmit blocks in both of the pluralities of block pairs, for use as a baseline clock by the respective digital clock generation circuitry in each of the transmit blocks in both of the pluralities of block pairs. Where each plurality includes N block pairs, the two dies together form a single 2N-lane device.