1. Tallinn Technical University
MIXDES, Sczcecin, June 26, SEQUENTIAL CIRCUITS BIST WITH STATUS BIT CONTROL
J.Raik, E.Orasson, Raimund Ubar
Tallinn Technical University
Estonia

2. Abstract DfT technique of BIST for sequential circuits is proposed
A subset of global feedback loops is chosen to make them deterministically controllable
Data path of a system is tested by pseudorandom patterns wheras the status lines entering the control part are cut and controlled deterministically to traverse all the branches in the FSM state transition graph

3. Mixed Pseudorandom Deterministic BIST
A mixed pseudorandom-deterministic technique for BIST of sequential circuits is proposed
Pseudorandom TPG
Signature analyzer

4. Mixed Pseudorandom Deterministic BIST
The main idea is: to force during pseudorandom testing the FSM to traverse all the branches in the state transition graph

5. Experimental Data P-random data with deterministic control of FSM
P-random with partially cut feedback loops
Pure pseudorandom

6. Conclusions Advantages of the method:
Partial scan instead of full scan
The system is tested at speed in its real functional modes
Low area overhead