Serial Interface Receiver Buffering for Stable Reference Voltage
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Solution Overview
Problem
In high-speed serial communication, the instability of the reference voltage due to leakage current in multiplexers used in serial interface receivers, particularly in multi-lane receivers, leads to increased error probabilities.
Innovation Solution
A serial interface receiver design that includes a first and second multiplexer to select reference voltages, a comparator, and a reference generator using a unity gain buffer to generate a buffer reference voltage, mitigating leakage current effects through offset calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If super low threshold voltage SLVT switch and/or low threshold voltage LVT switch is used in the MUX to secure bandwidth for high-speed operation, then bandwidth is improved, but leakage current increases which affects the stability of the reference voltage VREF
Solution Approach 1:
A buffer circuit is introduced as an intermediary component between the MUX and the reference voltage input terminal of the comparator. The buffer isolates the low-threshold-voltage switches in the MUX from directly affecting the reference voltage, preventing leakage current from degrading voltage stability while maintaining high-speed operation capability.
Solution Approach 2:
The input path is segmented into separate functional blocks: the MUX section handles high-speed signal switching with low-threshold-voltage switches, while the reference voltage input section uses a buffer to provide stable voltage reference. This segmentation allows each section to be optimized independently for its specific function.
2Productivity
If the number of lanes is increased in a multi-lane receiver to increase data transmission capacity, then productivity is improved, but the magnitude of leakage current increases which increases error probability
Solution Approach 1:
Each lane in the multi-lane receiver is independently equipped with its own buffer circuit at the comparator input. This per-lane segmentation prevents leakage current from accumulating across multiple lanes, allowing the receiver to scale to higher lane counts while maintaining signal integrity and low error rates.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design stabilizes the reference voltage, reducing error probabilities by blocking leakage current and ensuring reliable data transmission even in high-speed operations.
Implementation Method 1
a voltage follower to generate a buffer reference voltage from the reference voltage
Implementation Method 2
a comparator configured to compare the data signal with the buffer reference voltage
Implementation Method 3
a first multiplexer configured to select one of a data signal or a first reference voltage based on an enable signal
Data Source
AI summary
Disclosed is a receiver of a serial interface, comprising, a first multiplexer configured to select one of a data signal and a first reference voltage in response to an enable signal, a second multiplexer configured to select one of the first reference voltage and a second reference voltage in response to the enable signal, a comparator receiving an output of the first multiplexer to a positive input terminal and an output of the second multiplexer to a negative input terminal, and a reference generator configured to generate the second reference voltage and to generate the first reference voltage from the second reference voltage using an unity gain buffer.