Semiconductor Memory CA Multiplexing for Low-Speed Testing
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Solution Overview
Problem
Semiconductor memory devices face challenges in testing due to high data transfer rates exceeding the speed limit of test equipment, and existing techniques fail to support high-speed data transfer rates effectively.
Innovation Solution
The semiconductor memory device and memory module are designed to operate in multiple modes, allowing for normal operation at high-speed data transfer and a low-speed mode for testing, by generating output CA signals using a single input CA signal in normal mode and combining multiple input CA signals in low-speed mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the data transfer rate of semiconductor memory devices is increased to achieve higher capacity and speed, then productivity and performance are improved, but the device becomes incompatible with standard test equipment that has speed limits
Solution Approach 1:
The semiconductor memory device dynamically switches between a first operation mode (normal high-speed mode) and a second operation mode (low-speed test mode) based on the rate of receiving CA signals. The device adapts its operational characteristics to match the capabilities of connected equipment, enabling both high-speed data transfer and compatibility with standard test equipment that has speed limits.
2Adaptability or versatility
If multiple input CA signals are multiplexed to generate output CA signals in low-speed mode, then compatibility with standard test equipment is achieved, but the device complexity increases
Solution Approach 1:
The multiplexing circuit is designed to perform multiple functions: in the first operation mode, it operates as a simple signal pass-through with minimal processing, while in the second operation mode, it multiplexes multiple input CA signals to generate output CA signals. This multi-functionality allows the same circuit to support both high-speed normal operation and low-speed testing without requiring separate dedicated circuits for each mode.
3Ease of manufacture
If the semiconductor memory device operates in low-speed mode to accommodate test equipment limitations, then ease of testing is improved, but the productivity and data transfer efficiency decrease
Solution Approach 1:
The device dynamically adjusts its operational mode based on the testing or normal operation requirement. During testing, the device operates in low-speed mode to accommodate test equipment limitations, enabling ease of testing. During normal operation, the device switches to high-speed mode to maximize data transfer rate and productivity. This dynamic adaptation resolves the contradiction between ease of testing and productivity.
Data Source
AI summary
A semiconductor memory device includes a receiving circuit, a multiplexing circuit, a decoding circuit and a memory cell array. The receiving circuit receives a plurality of input command/address (CA) signals, and generates a plurality of CA signal groups based on the input CA signals and a clock signal. The multiplexing circuit operates in one of a first operation mode and a second operation mode based on a mode selection signal, outputs the plurality of CA signal groups as a plurality of selected CA signal groups in the first operation mode, and generates the plurality of selected CA signal groups by multiplexing the plurality of sub-CA signals included in the plurality of CA signal groups in the second operation mode. The decoding circuit generates a plurality of output CA signals based on the plurality of selected CA signal groups.