Fault detection for linear analog circuits using current injection
Jaime Velasco-Medina, T. Calin, M. Nicolaidis · 1998
A new test technique for linear analog circuits which employs current injection as input test stimulus is described. Our investigations have shown that current transitions resulting from a current injected on internal test points are significantly different for the fault free and faulty circuits. This can be used for fault detection purposes. In fact, the current injection as test input stimulus represents a powerfull alternative to the test approaches based on conventional voltage input stimulus. The new approach allows to improve the testability of various faults, which are difficult to detect or are untestable when using voltage-based test stimulus. In addition the technique has significant advantages for BIST testing purposes. The technique is illustrated by means of a modern opamp circuit and by considering catastrophic and gate-oxide-short (GOS) faults. Mixed-signal integrated circuits can accommodate a complete system-on-a-chip, resulting in reduced demands on board space, increased reliability, lower system costs and simpler design and manufacturing processes. While demand continues to rise for complete system-on-a-chip applications, in fields as diverse as telecommunications, automotive, consumer products and industrial controllers, the design and test of complex analog and mixed-signal integrated circuits is continually a difficult and challenging task. The analog components are often difficult to test and they can significantly increase the complexity of testing the overall mixed-signal integrated circuit or system. Circuits of small to medium complexity like operational amplifiers and filters have been *This research has been partially supported by Colciencias-Univalle † He is currently an assistant professor in Electrical Engineering