ODT State Output During Memory Read for Accurate Data Testing
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Solution Overview
Problem
Conventional semiconductor memory devices cannot determine the on/off state of the on-die termination (ODT) circuit during a data read operation, which affects the accuracy of read data.
Innovation Solution
A semiconductor memory device and method that include an ODT state information output unit to provide an ODT state information signal indicating whether the ODT circuit is on or off, using an ODT control signal during a data read mode, allowing the ODT circuit to be turned on or off and outputting this information via a data input/output pad.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ODT circuit is turned on during data read operation, then signal integrity is improved, but read data accuracy deteriorates
Solution Approach 1:
The ODT circuit is designed to dynamically change its state based on the operating mode. During data read operations, the ODT circuit is turned off to ensure accurate reading. During data write operations, the ODT circuit is turned on to improve signal integrity. This dynamic switching resolves the contradiction by adapting the ODT circuit's state to the specific operational requirements.
2Device complexity
If the ODT circuit state is not monitored during data read mode, then device complexity is reduced, but measurement capability deteriorates
Solution Approach 1:
The existing data input/output pad is made multi-functional by enabling it to output both normal data and ODT state information. By configuring the pad to output ODT state information under specific conditions (when ODT detection is enabled), the patent achieves state monitoring without adding dedicated monitoring hardware, thus maintaining low device complexity while improving measurement capability.
3Measurement precision
If the ODT state information is output during data read mode, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The ODT state information is output through the existing data input/output pad that is already present in the memory device. By utilizing this existing infrastructure for dual purposes (data transmission and ODT state output), the patent avoids the need for additional dedicated output circuits, thereby improving measurement precision while minimizing the increase in device complexity.
Data Source
AI summary
A semiconductor memory device for testing whether an ODT circuit is on or off during a data read mode includes an on-die termination (ODT) circuit and an ODT state information output unit. The ODT circuit includes at least one ODT resistor. The ODT state information output unit outputs an ODT state information signal indicating whether the ODT circuit is on or off, in response to an ODT control signal during a data read mode when data is output from memory cells. With a semiconductor memory device and method capable of testing whether an ODT resistor is on or off during a data read mode, it is possible to test whether an ODT circuit is on or off during reading of data.