On-Die Termination Dynamic Impedance Control
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Solution Overview
Problem
On-die termination (ODT) circuits in memory devices can attenuate the transmitter signal when memory dies are electrically close, leading to deterioration of signal integrity due to ineffective termination of reflections on the bus.
Innovation Solution
Implementing ODT relinquish modes that allow memory dies to deactivate ODT when another die is transmitting, based on command detection and mode register settings, using ODT control circuitry to dynamically change impedance and manage signal termination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ODT is applied by non-transmitting memory dies to reduce reflections on the bus, then signal reflections are reduced, but the transmitter signal is attenuated when memory dies are electrically close
Solution Approach 1:
The patent implements dynamic ODT control where the impedance state of memory dies is changed based on real-time detection of transmission activity. Non-transmitting dies dynamically switch between high-impedance (ODT disabled) and low-impedance (ODT enabled) states according to whether another die is currently transmitting, allowing the system to adapt to varying operational conditions and eliminate both reflections and attenuation issues
2Object-affected harmful factors
If ODT is continuously applied by non-transmitting memory dies, then reflections are terminated, but time constraints are violated due to unnecessary impedance changes
Solution Approach 1:
The patent implements periodic ODT activation where non-transmitting dies only enable their ODT circuits during specific time windows when another die is detected to be transmitting. This periodic action is controlled by detecting transmission activity and enabling ODT only during relevant periods, thereby avoiding unnecessary impedance changes and meeting strict time constraints while still providing reflection termination when needed
3Reliability
If ODT impedance is dynamically changed based on transmission detection, then signal integrity is improved, but device complexity increases due to additional control circuitry
Solution Approach 1:
The patent implements self-service ODT control where each memory die independently monitors the bus for transmission activity and autonomously adjusts its own ODT impedance state without requiring external control signals or complex centralized coordination. This self-service approach enables intelligent ODT management while minimizing additional circuitry complexity, as each die only needs basic transmission detection capability and internal ODT control
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
Improves signal integrity by preventing attenuation of the transmitter signal and ensuring effective termination of reflections, complying with stricter time constraints in memory devices.
Implementation Method 1
On-die termination (ODT) circuits may apply an impedance that operates to reduce reflections on a bus
Data Source
AI summary
Apparatuses and methods are disclosed herein, including those, performed by a memory die, that operate to detect that a command on a bus connected to the memory die is addressed to another memory die responsive to a chip select signal, and to change the impedance of an on-die termination circuit of the memory die responsive to the detecting.