BISCC: Efficient pre through post silicon validation of mixed-signal/RF systems using built in state consistency checking.

High levels of integration in SoCs and SoPs is making pre as well as post-silicon validation of mixed-signal systems increasingly difficult due to: (a) lack of automated pre and post-silicon design checking algorithms and (b) lack of controllability and observability of internal circuit nodes in post-silicon. While digital scan chains provide observability of internal digital circuit states, analog scan chains suffer from signal integrity, bandwidth and circuit loading issues. In this paper, we propose a novel technique based on built-in state consistency checking that allows both pre as well as post-silicon validation of mixed-signal/RF systems without the need to rely on manually generated checks. The method is supported by a design-for-validation (DfV) methodology which systematically inserts a minimum amount of circuitry into mixed-signal systems for design bug detection and diagnosis purposes. The core idea is to apply two spectrally diverse stimuli to the circuit under test (CUT) in such a way that they result in the same circuit state (observed voltage/current values at internal or external circuit nodes). By comparing the resulting state values, design bugs are detected efficiently without the need for manually generated checks. No assumption is made about the nature of the detected bugs; the stimulus applied is steered towards those that are the most likely to detect design bugs. Test cases for both pre and post-silicon design bug detection and diagnosis prove the viability of the proposed BISCC approach.