10GBase-T Analog Front End Clock Distribution for EMI and SNR
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Solution Overview
Problem
In high-speed transceivers, substrate noise and electromagnetic interference (EMI) cause constructive interference among multiple transmit clocks, limiting chip performance and reducing signal-to-noise ratios (SNR), while using multiple clocks consumes power and chip space.
Innovation Solution
A method for simultaneous clocking in an analog front end, where a central clock generator distributes a single transmit clock to phase interpreters and transmitter/receiver ports, allowing independent adjustment of transmit and receive clock phases using a feedback algorithm to balance clock delays and phases, thereby controlling EMI and optimizing SNR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multiple transmit clocks are used to manage transmit clock phase of each channel, then EMI and substrate noise are reduced, but power consumption increases and chip space is consumed
Solution Approach 1:
The patent merges multiple transmit clock sources into a single clock generator that produces one master transmit clock signal. This single clock is then distributed to multiple channels through phase interpolators, reducing the number of clock sources from multiple to one, thereby reducing power consumption and chip space while maintaining the ability to control phase relationships between channels.
Solution Approach 2:
The single transmit clock generator serves multiple channels simultaneously, and the phase interpolators enable this single clock to provide independently phased clock signals to multiple transmit paths. This multi-functional approach allows one clock source to replace multiple dedicated clock sources, reducing power and space while maintaining channel independence.
2Reliability
If multiple transmit clocks are used to manage transmit clock phase of each channel, then chip performance is improved, but power consumption increases and chip space is consumed
Solution Approach 1:
Multiple clock sources are merged into a single clock generator that produces one master transmit clock. This consolidated approach reduces the quantity of clock-related components on the chip, freeing up chip space while maintaining performance through phase interpolation technology that preserves channel independence.
Solution Approach 2:
The patent changes the parameter of clock phase by using phase interpolators that can adjust the phase of the single transmit clock signal for each channel independently. This parameter adjustment capability maintains chip performance by allowing precise phase control without requiring multiple physical clock sources, thereby reducing chip space consumption.
3Reliability
If multiple transmit clocks are used to manage transmit clock phase of each channel, then chip performance is improved, but resources such as power and chip space are consumed
Solution Approach 1:
The patent combines multiple clock sources into a single clock generator, reducing device complexity by eliminating redundant clock circuits. The single clock signal is then distributed to multiple channels through phase interpolators, which add minimal complexity compared to multiple independent clock sources, thereby improving chip performance with reduced device complexity.
4Use of energy by moving object
If a single transmit clock is used for all channels, then power consumption is reduced and chip space is conserved, but EMI and substrate noise increase due to constructive interference
Solution Approach 1:
Multiple clock sources are merged into one, reducing power consumption and eliminating the harmful effects of multiple clocks. The phase interpolator technology enables this single clock to provide independently phased signals to different channels, preventing constructive interference and the associated EMI and substrate noise issues.
Solution Approach 2:
The patent changes the phase parameter of the single transmit clock signal for each channel using phase interpolators. By independently adjusting the phase of the clock signal delivered to each channel, the system prevents constructive interference between channels, thereby reducing EMI and substrate noise while maintaining the power and space benefits of a single clock source.
5Quantity of substance
If a single transmit clock is used for all channels, then chip space is conserved, but EMI and substrate noise increase due to constructive interference
Solution Approach 1:
Multiple clock sources are merged into a single clock generator, conserving chip space by eliminating redundant clock circuits. The phase interpolator technology enables this single clock to provide independently phased signals to different channels, preventing constructive interference and the associated EMI and substrate noise issues.
Solution Approach 2:
The patent changes the phase parameter of the single transmit clock signal for each channel using phase interpolators. By independently adjusting the phase of the clock signal delivered to each channel, the system prevents constructive interference, thereby reducing EMI and substrate noise while maintaining the chip space benefits of a single clock source.
Data Source
AI summary
A 10GBASE-T clocking method that limits EMI and increases SNR, while reducing power and conserving chip space is provided. The method includes simultaneous clocking of transmitters in an analog front end of a 10 gigabit Ethernet. The method includes providing at least two channels to a 10GBase-T analog front end, where the channel has at least a transmitter port and a receiver port, and providing at least two phase interpreters to the analog front end, where each phase interpreter is dedicated to one receiver port. A central clock generator is disposed to distribute a transmit clock to the phase interpreters and to the transmitter ports, where the transmit clock is further provided to the receiver ports from the phase interpreters. Any clock delay between the clock generator and each channel is balanced and clock phases between the channels are matched.