In this paper a multi-mode signature analyser is proposed to be built into analog and mixed-signal integrated circuits. The analyser circuitry is based on analog integrators and can perform transient (with one integrator) and frequency (with two integrators) response compaction. The area overhead incurred can be very low, since the same signature analyser can be shared by several analog macros. Besides that, whenever integrators are available on-chip for functional purposes, they can be shared with the testing circuitry. Experiments carried on a Sallen-Key (transient response compaction) and on a biquad filter (frequency response compaction) showed that a very high coverage of catastrophic and pammetric faults can be obtained by using the proposed multi-mode signature analyser.