Configurable On-Die Termination for Adaptive Differential Receivers
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Solution Overview
Problem
Conventional high-speed data communication integrated circuit (IC) systems face challenges in achieving customizable on-die termination (ODT) configurations to meet diverse customer requirements, such as power-efficiency, termination voltages, and impedances.
Innovation Solution
The implementation of configurable on-die termination (ODT) circuitry that allows for programmable termination topologies, such as rail-to-rail and half-supply configurations, with adjustable impedances and switchable termination legs, enabling dynamic selection of termination characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional fixed ODT configurations are used, then circuit design is simple, but customer requirements for different termination voltages and impedances cannot be met
Solution Approach 1:
The patent implements dynamic ODT configurations by introducing switchable termination legs that can be programmed to connect different termination impedances and voltage references. The ODT circuit transitions from a fixed configuration to a dynamic one where termination characteristics can be changed via control signals, allowing customers to select from multiple termination topologies (rail-to-rail, half-supply, etc.) without changing the physical circuit design.
Solution Approach 2:
The patent changes the parameters of the ODT circuit by providing multiple termination impedances (e.g., 50 ohms, 75 ohms, 100 ohms) and multiple voltage references (e.g., VDD/2, VDD, ground) that can be selectively connected. This allows the termination voltage and impedance parameters to be adjusted according to customer requirements while maintaining a single integrated circuit design.
2Adaptability or versatility
If multiple ODT configurations are provided, then customer requirements are better met, but power consumption increases
Solution Approach 1:
The patent uses dynamic switching to enable multiple termination configurations. Only one termination leg is active at any given time, controlled by switchable elements that connect the appropriate termination impedance and voltage reference. This dynamic approach allows the circuit to provide multiple termination topology options (rail-to-rail, half-supply, etc.) while consuming power only for the currently active configuration, not all possible configurations simultaneously.
3Manufacturing precision
If fixed termination impedances are used, then manufacturing is simpler, but impedance matching precision is insufficient for high-speed communication
Solution Approach 1:
The patent provides multiple discrete termination impedance values (e.g., 50 ohms, 75 ohms, 100 ohms) that can be selectively connected via switches. This allows the impedance parameter to be adjusted to precisely match the transmission line characteristic impedance, improving impedance matching accuracy for high-speed communication. The circuit structure includes multiple impedance elements but uses switching to activate only the needed one, managing the complexity.
Data Source
AI summary
Described are integrated-circuit die with differential receivers, the inputs of which are coupled to external signal pads. Termination legs coupled to the signal pads support multiple termination topologies. These termination legs can support adjustable impedances, capacitances, or both, which may be controlled using an integrated memory.