Design and test of analog circuits towards sub-ppm level

Abstract

Electronics are increasingly being embedded in a growing number of applications in our daily life. This demands strong reliability and robustness of those electronic systems. The IC manufacturing process not being perfect, however, inevitably results in some fabricated parts having defects. Test methods must detect such faulty ICs before shipment. While the fault coverage of testing for digital integrated circuits in industry today already reaches the sub-ppm level, this is not yet the case for analog integrated circuits or the analog part in mixed-signal ICs. This invited talk will review some techniques that are being explored in industrial practice to aim for sub-ppm-level coverage for the analog and mixed-signal circuits as well. This will be illustrated with some practical examples from automotive IC designs.

SymBIST: Symmetry-Based Analog and Mixed-Signal Built-In Self-Test for Functional Safety

“…Thus, each sub-DAC can set 2 5 − 1 = 31 comparison levels. VREF [1] to VREF [31] denote these comparison levels, VREF[0]=GND, and VREF [32]=VREFP. The midscale voltage is VREF [16].…”

“…This implies that the functional safety of individual ICs must increase to prevent decrease in the system's functional safety. More specifically, it is desired that test escapes are in the order of sub-ppm [1].…”

“…A defect is always considered a potential threat and reliability hazard. An IC with a detected defect should be preferably discarded for safety reasons [1], [3], [4]. Even if from a functional viewpoint the performance complies with the specifications promised in the datasheet during post-manufacturing test time, e.g.…”

A very low cost and highly parallel DfT method for analog and mixed-signal circuits

“…This empirical approach results in long and expensive test sets which cause analog testing to dominate the testing effort and cost for mixed-signal ICs. Furthermore, these specification-based tests often lead to poor fault coverage for the analog circuits, since the possible defects are not directly addressed in such a methodology [1].…”

Non-intrusive detection of defects in mixed-signal integrated circuits using light activation

“…This rather empirical approach results in long and expensive test sets which cause analog testing to dominate the testing effort and cost for mixed-signal ICs. Furthermore, these specification-based tests often lead to poor fault coverage, since the possible defects are not directly addressed in such a methodology [2], [3].…”