
9.5 STUCK-AT FAULTS AND THE EFFECT OF HAZARD COVER 413
FIGURE 9.20
Effect of stuck-at fault on function N
XOP
in Eq. (9.12). (a) AND representing the A
¯
BCD term and
showing a stuck-at fault on input C. (b) Timing diagram showing effect of the stuck-at 0 fault and the
masking effect of hazard cover.
two-level SOP or POS counterparts. This, of course, is one advantage in the use of XOP,
EOS, and CRMT circuits discussed in Chapter 5. However, if static hazards must be elimi-
nated in these circuits prior to fault testing, this advantage may be lessened or eliminated.
Static hazard cover must always be redundant cover (i.e., not essential to function represen- ...