Semiconductor Memory Calibration Circuit for Setup Hold Timing
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Solution Overview
Problem
Conventional semiconductor device calibration circuits require extensive time and resources to recalibrate set-up/hold values due to variations in process, voltage, or temperature, especially when the values are not compatible with operating frequency conditions, leading to inefficiencies in data transmission.
Innovation Solution
A calibration circuit for semiconductor devices that includes a data input buffer, data latch, data generator, data tester, and calibration unit, which uses shift signals to calibrate output times and delay paths, allowing for internal data input and sequential control of delay times based on interlock checks between data and strobe signals, thereby reducing calibration time and ensuring compatibility regardless of process, voltage, or temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequency test is performed after package assembly to secure set-up/hold value, then set-up/hold value is guaranteed, but time and resources are wasted due to recalibration needed when process variation occurs
Solution Approach 1:
The patent applies preliminary action by performing set-up/hold value calibration during wafer fabrication using fuse options before package assembly. This allows the calibration to be completed in advance, eliminating the need for time-consuming recalibration after packaging when process variations occur. The internal delay mechanism is pre-configured to compensate for expected process variations.
Solution Approach 2:
The patent implements self-service through an internal delay mechanism that automatically adjusts timing parameters based on detected process variations. The system uses internal feedback to self-correct set-up/hold values without requiring external recalibration, thereby reducing calibration time and resource consumption while maintaining reliability.
2Reliability
If frequency test is performed after package assembly, then set-up/hold value is secured, but resources are wasted due to repeated calibration processes
Solution Approach 1:
The calibration process is moved to the wafer fabrication stage before package assembly, allowing set-up/hold values to be predetermined and stored in fuse options. This preliminary calibration eliminates the need for repeated resource-intensive frequency tests after packaging, reducing overall energy consumption and resource waste while maintaining product reliability.
3Ease of operation
If delay option of data input buffer is controlled to calibrate data-strobe difference, then interface timing is optimized, but recalibration is required from start when process variation occurs
Solution Approach 1:
The patent introduces a dynamic internal delay mechanism that can automatically adjust timing parameters in response to process variations. Instead of requiring manual recalibration from scratch, the system dynamically adapts the delay options of the data input buffer based on detected timing deviations, maintaining interface optimization while improving calibration efficiency.
Solution Approach 2:
The system implements feedback by monitoring the actual timing relationship between data and strobe signals and using this information to automatically adjust the internal delay mechanism. This closed-loop approach allows the system to maintain optimal interface timing without requiring complete recalibration when process variations occur, thereby improving productivity.
Data Source
AI summary
A calibration circuit for a semiconductor device and a method of driving the same. The calibration circuit includes a PRBS generator in which a data pattern is generated within an integrated circuit without receiving data from the outside, a PRBS tester that compares output signals of a data latch that strobes and latches an output signal of a data input buffer to determine whether the interlock operation of data and strobe is pass or fail, and a calibration unit that calibrates a delay time using the output signal of the PRBS tester as much as a predetermined unit. Thus, variation in process, voltage, temperature, etc. can be freely calibrated even after package assembly. Accordingly, it is possible to guarantee a set-up/hold value that is necessary for high frequency operation of a system, and to reduce the time and resources necessary for product manufacture and for calibrating these values.