A built-in electrical test circuit for interconnect tests in assembled PCBs

In this paper, a built-in electrical test circuit is proposed to detect an open defect at an interconnect between a land in a printed circuit board and an IC. An inverter gate is used as an open sensor in the test circuit. An AC voltage signal is provided to a targeted interconnect and the sensor as a test input signal to detect the defect. The defect is detected by means of supply current of the sensor. We examine by Spice simulation whether open defects can be detected with the test circuit. The results reveal us that an open defect can be detected at a test speed of 1 MHz for each interconnect.