Memory Interface Circuit Layout for DRAM Clock-Data Timing Match
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Solution Overview
Problem
In DRAM circuits, the mismatch between data paths and clock paths leads to timing violations, particularly evident in the difference tDQS2DQ, which affects the alignment of write data edges with the clock signal, causing inefficiencies and potential errors in data transmission.
Innovation Solution
The interface circuit design centrally arranges input buffer circuits relative to the clock pad, reducing the clock path length and improving the matching between data and clock paths, thereby reducing timing violations and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If data pads are arranged in a linear fashion with input buffer circuits positioned far from the clock pad, then the layout is simple and easy to manufacture, but the clock path length increases causing timing violations and increased power consumption
Solution Approach 1:
The patent transitions from a linear one-dimensional arrangement of pads to a two-dimensional layout where data pads are positioned on both sides of the clock pad in a row, and input buffer circuits are arranged in a separate row closer to the clock pad. This dimensional change allows simultaneous optimization of timing performance and manufacturing simplicity by creating a compact yet symmetric structure.
Solution Approach 2:
The patent employs asymmetric positioning where input buffer circuits are placed closer to the clock pad than the data pads, creating unequal distance relationships that optimize timing. Specifically, the distance from the clock pad to input buffer circuits is reduced while data pads maintain their functional positioning, achieving better timing without compromising manufacturing simplicity.
2Stability of the object's composition
If input buffer circuits are positioned far from the clock pad, then the data path length is sufficient for signal stability, but the clock path length increases causing timing mismatches between clock and data signals
Solution Approach 1:
The patent applies different positioning strategies to different circuit components: input buffer circuits are positioned closer to the clock pad to optimize clock path timing, while data pads maintain their traditional positioning to ensure data signal stability. This localized optimization allows each component to be positioned for its specific functional requirements rather than using a uniform arrangement.
3Adaptability or versatility
If the clock path length is increased to reach distant input buffer circuits, then all input buffers can be reached by the clock signal, but power consumption increases due to the longer clock signal transmission path
Solution Approach 1:
The patent segments the input buffer circuits into two groups positioned on opposite sides of the clock pad, allowing the clock signal to reach all buffers through a compact arrangement. This segmentation enables the clock tree to be distributed efficiently without requiring excessive signal path length, thereby reducing power consumption while maintaining full coverage of all input buffers.
Data Source
AI summary
An interface circuit, a data transmission circuit and a memory are provided. The interface circuit includes a clock pad, data pads and input buffer circuits, where the clock pad and the data pads are arranged in the first row, and the M data pads are arranged on two sides of the clock pad, half of the M data pads being arranged on each side, where the M input buffer circuits are arranged in the second row and form an axis perpendicular to the first row with the data pads as reference, and the M input buffer circuits are arranged on two sides of the axis, half of the M input buffer circuits being arranged on each side, and where the distance between each input buffer circuit and the axis is smaller than the distance between the data pad corresponding to the input buffer circuit and the axis.