A novel approach to I/sub DDQ/ testing of mixed-signal integrated circuits

Abstract

This paper presents an effective built-in current sensor (BICS), which has a very small impact on the performance of the circuit under test (CUT). The proposed BICS works in two-modes the normal mode and the test mode. In the normal mode, the BICS is isolated from the CUT due to which there is no performance degradation of the CUT. In the testing mode, our BICS detects the abnormal current caused by permanent manufacturing defects. Furthermore, our BICS can also distinguish the type of defect induced (gate-source short, source-drain short and drain-gate short). Our BICS requires neither an external voltage source nor current source. Hence the BICS requires less area and is more efficient than the conventional current sensors. The circuit under test is a 10-bit digital-to-analog converter using charge-scaling architecture.