Memory Timing Characterization Using Distributed Capture Flip-Flops
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing memory IP timing characterization techniques face challenges in accurately measuring on-chip timing parameters due to the complexity of memory devices with multiple address, write-data, clock, and data-out inputs/outputs, and the physical distance between these components, leading to measurement errors and increased complexity.
Innovation Solution
A fully configurable synthesizable memory IP timing characterization test bench is implemented, featuring distributed regional capture flip-flops with a mesh-based low skew clock and main capture flip-flop circuits to measure setup differences, along with multiple data/input delay generators and XORed clock delay generators to handle timing permutations and minimize measurement errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional timing characterization techniques are used for memory devices, then the measurement process becomes simpler, but measurement precision deteriorates due to physical distance and complexity of memory components
Solution Approach 1:
The test bench is segmented into multiple specialized functional blocks: delay generators for precise timing control, capture flip-flops for synchronized sampling, XOR gates for differential measurement, and multiplexers for signal routing. Each block handles a specific aspect of timing characterization, reducing overall system complexity while improving measurement precision through dedicated functionality.
Solution Approach 2:
Delay generators are introduced as intermediary components between the clock signal source and the memory device inputs. These intermediaries provide programmable delay to align timing signals, enabling accurate measurement of setup and hold times without requiring direct connection between clock and data signals, thus improving measurement accuracy while managing complexity.
2Adaptability or versatility
If multiple address, write-data, clock, and data-out inputs/outputs are used in memory devices, then functionality is improved, but measurement errors increase due to physical distance between components
Solution Approach 1:
The measurement approach transitions from spatial proximity consideration to temporal synchronization by introducing programmable delay generators. Instead of relying on physical proximity to minimize errors, the system uses time-domain adjustments through delay elements to align signals from various memory inputs/outputs, enabling accurate timing measurement across distributed components.
Solution Approach 2:
Capture flip-flops are used to sample and hold timing information from multiple memory signals, creating feedback points that allow measurement of timing relationships. The XOR gates compare sampled signals to detect timing violations, providing feedback information about setup and hold time margins, thus enabling accurate timing characterization despite physical distance between components.
3Productivity
If on-chip timing characterization is implemented, then productivity is improved through built-in self-test, but device complexity increases due to additional circuitry
Solution Approach 1:
The timing characterization circuitry is designed with universal components that can test multiple memory timing parameters using the same hardware blocks. Delay generators, capture flip-flops, and XOR gates are configured through control signals to measure different timing characteristics (setup time, hold time, clock-to-output time) across various memory inputs and outputs, achieving high productivity without proportionally increasing complexity.
Solution Approach 2:
The test bench implements built-in self-test capability where the memory device under test is characterized using on-chip resources without requiring external testing equipment. The circuitry uses itself as the test object, generating test signals, capturing responses, and evaluating timing parameters internally, thereby improving productivity through integrated testing while managing complexity through resource sharing.
Data Source
AI summary
An apparatus includes a plurality of delay generators, a first plurality of flip-flop circuits, a second plurality of flip-flop circuits, and a third plurality of flip-flop circuits. The plurality of delay generators includes a data delay generator, an enable delay generator, and a reference delay generator. The first plurality of flip-flop circuits is coupled to the data delay generator to receive a delayed data input signal, and provide the delayed data input signal to a plurality of data input terminals of a memory circuit. The second plurality of flip-flop circuits is coupled to the enable delay generator to receive a delayed enable signal and provide the delayed enable signal to a plurality of enable terminals of the memory circuit. The third plurality of flip-flop circuits is coupled to an output terminal of the memory circuit. The reference delay generator provides a synchronized clock signal to the flip-flop circuits.