DFT (Design for test) Analog / BIST

Analog test

Generally speaking, an analog test is quite difficult compared to a digital test. On one hand an error is not that clear (for example is a circuit bad if it is OK with a supply voltage of 1.8V but not with 1.799V?) and the test consumes more time. Therefore one normally uses a step response to test the analog part of the circuit in the final products. Furthermore, some connections might be forwarded to the outside world.

BIST (Built in self Test)

Is made because production test is expensive and the production test is maybe not fast enough to test some timing faults. Therefore, one could implement a BIST where the test vectors are already saved in the IC and also compared there. It is normally used to test storage elements like RAM, Rom.

Print Friendly, PDF & Email

Leave a Reply