Transient response analysis (TRA) [1-4] is an emerging technique for testing linear sub-systems embedded in mixed-signal integrated circuits. Digital-to-analogue converters (DACs) are a special case of mixed-signal cells which appear at the boundaries of the two subsystems and encompass specialist test problems [4]. This paper describes how pass/fail limits are set in a production test through an analysis of functional defects, and presents a new normalising process permitting extra discernibility in transient response analysis.