On-line testable decimation filter design for AMS systems

This paper presents an implementation of on-line testing techniques for the case of a decimation filter. The decimation filter is used in a ΣΔ analogue-to-digital converter that is in turn used in a built-in-self-test (BIST) circuitry for mixed-signal core testing. Thus, the filter itself must be self-testable. Three different one-line self-test techniques are studied and compared for a 0.18 μm CMOS technology. The first one uses a non-concurrent structural test technique and the others are both based on semi-concurrent test methodologies. In all cases, the on-line test circuitry is automatically synthesized and exploits the idle time of the functional units to apply either a structural or a functional test.