Serializer Output Line Layout for Low-Resistance High-Speed Data
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Solution Overview
Problem
Semiconductor devices, such as LPDDR5 DRAM, face challenges in reducing the resistance of output nodes to manage high-frequency serial data conversion efficiently, particularly in parallel to serial and serial to parallel conversion operations synchronized with different phase clock signals.
Innovation Solution
The semiconductor device incorporates a read clock synchronization circuit and a data output circuit block with tristate buffer circuits and a buffer circuit, optimizing the layout and connectivity to minimize line resistance and ensure high-speed data transfer by adjusting impedance, driver strength, and slew rate, thereby reducing data delay and enabling high data transfer rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the frequency of serial data output is increased to achieve high data transfer rates, then productivity is improved, but line resistance increases causing data delay and signal integrity degradation
Solution Approach 1:
The patent applies local quality by optimizing the output node specifically where high-frequency serial data is generated. Tristate buffer circuits are positioned at the output node to provide localized impedance control and signal driving capability, ensuring that the critical high-frequency signal path has reduced resistance without requiring changes to the entire data bus structure.
Solution Approach 2:
The patent implements dynamic control through tristate buffer circuits that can dynamically switch between high-impedance and low-impedance states. This dynamic impedance adjustment allows the output node to maintain low resistance during active data transmission at high frequencies, while reducing power consumption and signal interference when data transmission is not occurring.
2Speed
If the resistance of the output node is reduced to minimize data delay, then speed is improved, but device complexity increases due to additional buffer circuits and layout optimizations
Solution Approach 1:
The patent merges the functions of multiple circuit elements into the tristate buffer circuit configuration. The tristate buffers combine signal buffering, impedance matching, and output driving functions in a single circuit structure, reducing the need for separate components and simplifying the overall output stage design while maintaining high-speed performance.
Solution Approach 2:
The patent addresses the resistance-speed contradiction by transitioning from a single-dimensional approach (simple wire connection) to a multi-dimensional solution involving vertical stacking of buffer circuits and three-dimensional layout optimization. This allows reduced resistance through optimized current paths without proportionally increasing the horizontal footprint or overall device complexity.
3Productivity
If tristate buffer circuits are used to reduce output node resistance, then productivity is improved, but manufacturing precision requirements increase due to layout and connectivity optimizations
Solution Approach 1:
The patent segments the output driver into multiple tristate buffer circuits that can be independently optimized and manufactured. Each buffer circuit is designed as a modular unit with standardized layout patterns, allowing for precise manufacturing through repeated unit structures. This segmentation enables better control over interconnect lengths and impedance matching while maintaining high data transfer rates.
Data Source
AI summary
Disclosed herein is an apparatus that includes an output signal line, and first and second tristate buffer circuits each having an output node connected to the output signal line in common. The output signal line includes a first section having first and second connection points, a second section having third and fourth connection points, a third section connected between the first and third connection points, and a fourth section connected between second and fourth connection points. At least a part of the first section of the output signal line is located on the first tristate buffer circuit, and at least a part of the second section of the output signal line is located on the second tristate buffer circuit.