DAC Switching Network BIST for Faster Defect Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing complexity of integrated circuit design, particularly in digital to analog (DAC) circuits, leads to higher testing costs due to the need for extensive testing of all possible configurations, which is time-consuming and resource-intensive, especially as the number of bits increases, making it challenging to detect and localize silicon defects efficiently.
Innovation Solution
Implementing a built-in-self-test (BIST) circuitry within the DAC that reduces the number of tests required by applying a subset of input codes to detect failures in the switching network, allowing for a self-test mode that identifies defects within the DAC without external equipment, thereby reducing testing time and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all possible input codes are tested to detect silicon defects in DAC, then measurement precision and reliability are improved, but test time and device complexity increase significantly
Solution Approach 1:
The patent segments the switching network into multiple groups based on the binary representation of input codes. Instead of testing all 2^n codes sequentially, the test is divided into multiple phases where each phase tests a specific group of switches. This segmentation allows parallel testing of different switch groups, significantly reducing total test time while maintaining complete coverage of all switches.
Solution Approach 2:
The patent applies partial action by testing only the necessary subset of input codes that are sufficient to cover all switches in the DAC. Rather than exhaustively testing all possible input codes, the method identifies and tests only those codes that activate each switch at least once, achieving complete switch coverage with fewer test cases.
2Measurement precision
If all possible input codes are tested to detect silicon defects in DAC, then measurement precision and reliability are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent implements self-service by integrating the testing functionality directly into the DAC circuit itself. The DAC uses its own switching network and output circuitry to perform the test, eliminating the need for external test equipment. The circuit tests itself by applying test input codes and monitoring its own output, significantly simplifying the overall test architecture while maintaining comprehensive defect detection capability.
3Adaptability or versatility
If the number of bits in DAC is increased to improve configurability, then adaptability is improved, but the number of tests required increases exponentially
Solution Approach 1:
The patent segments the switching network into multiple groups based on the binary representation of input codes. Instead of testing all 2^n codes sequentially, the test is divided into multiple phases where each phase tests a specific group of switches. This segmentation allows parallel testing of different switch groups, significantly reducing total test time while maintaining complete coverage of all switches.
Solution Approach 2:
The patent applies partial action by testing only the necessary subset of input codes that are sufficient to cover all switches in the DAC. Rather than exhaustively testing all possible input codes, the method identifies and tests only those codes that activate each switch at least once, achieving complete switch coverage with fewer test cases.
Data Source
AI summary
A digital-to-analog converter (DAC) includes a switching network and built-in-self-test (BIST) circuitry. The DAC, in operation, generates analog output signals in response to input codes of a set of input codes of the DAC. The BIST circuitry sequentially applies codes of a determined subset of codes of the set of input codes to test the plurality of switches. The determined subset of codes has fewer codes than the set of input codes. The BIST circuitry detects failures of switches of the plurality of switches based on responses of the DAC to the applied codes. In response to detecting a failure of a switch, the BIST generates a signal indicating a failure of the switching network.