On-Chip Pseudorandom MEMS Testing

Abstract

This paper presents a Built-In-Self-Test (BIST) implementation of pseudo-random testing for MEMS. The technique is based on Impulse Response (IR) evaluation using pseudo-random Maximum--Length Sequences (MLS). The MLS approach is capable of providing vastly superior dynamic range in comparison to the straightforward technique using an impulse excitation and is thus an optimal solution for measurements in noisy environments and for low-power test signals. The use of a pseudo-random sequence makes the practical on-chip implementation very efficient in terms of the extra hardware required for on-chip testing. We will demonstrate the use of this technique for an on-chip fast and accurate broadband determination of MEMS behaviour, in particular for the characterisation of cantilever MEMS structures, determining their mechanical and thermal behaviour using just electrical tests.