A DFT Approach for Testing Embedded Systems Using DC Sensors

Abstract

In this article, we propose a sensor-based BIT scheme. By using sensors, we mitigate any issues related to signal integrity and diversity in the test response capture process. Also, BIT can provide a test framework to estimate specifications during production testing for various modules in a heterogeneous SoC or SiP. This scheme involves designing sensors for each module directly into the device under test (DUD and capturing sensor outputs that are low-frequency DC signals. A low-frequency mixed-signal tester can capture these sensor responses, analyze them to infer each specific module's performance, and determine the overall pass-fail decision for the DUT. The embedded sensors perform the necessary signal conditioning of the DUT output signals, thereby significantly reducing the ATE's response capture and analysis overhead. As an example, it's possible to test a digital module for rise time by incorporating an integrator at the output node as a sensor. As the output node voltage increases, the integrator's output capacitance charges to a DC value. The ATE samples the capacitor's DC voltage at a specific time, and the DC voltage would be proportional to the DUT's rise time. In this case, there would be no need to sample the rising waveform, and the ATE's digitizer requirements could be significantly relaxed. This example indicates that during production testing, carefully chosen sensors can effectively simplify the overall test procedure