BISCC: A Novel Approach to Built In State Consistency Checking For Quick Volume Validation of Mixed-Signal/RF Systems

The increasing integration of mixed-signal systems in System-on-Chips (SoCs) and System-on-Packages (SoPs) has made pre and post-silicon validation more challenging. This is due to the lack of automated design checking algorithms and the inability to control and observe internal circuit nodes in post-silicon. While digital scan chains can provide observability of internal digital circuit states, analog scan chains encounter issues such as signal integrity, bandwidth, and circuit loading. To address these challenges, a new approach based on built-in state consistency checking (BISCC) is proposed in this paper. The BISCC technique enables both pre and post-silicon validation of mixed-signal/RF systems without the need for manual checks. The approach is supported by a design-for-validation (DfV) methodology, which inserts a minimum amount of circuitry into mixed-signal systems to detect and diagnose design bugs. The core idea is to apply two spectrally diverse stimuli to the circuit under test (CUT) in a way that results in the same circuit state (observed voltage/current values at internal or external circuit nodes). By comparing the resulting state values, design bugs can be detected efficiently without manual checks. The proposed BISCC approach does not make assumptions about the nature of the detected bugs and is steered towards detecting the most likely design bugs. The effectiveness of the approach is demonstrated through test cases for both pre and post-silicon design bug detection and diagnosis.