Models in Memory Testing - Models in Hardware Testing - page 169

2. Disturb coupling fault ( CF ds ): an operation (write or read) performed on the
aggressor cell forces the victim cell into a given logic state. Any oper-
ation performed on the aggressor is accepted as sensitizing operation (a
read, a transition write, or a non-transition write). Twelve types of disturb

coupling faults exist, defined as CF ds .x z ; w y / D ˚ <x a z v ; w y = z v = > ,and
CF ds .x z ;r y / D f <x a y v ;r x = y v = > g where x; y; z 2 f 0; 1 g . This covers FP 5 ,
FP 6 ,FP 7 ,FP 8 ,FP 9 ,FP 10 ,FP 11 ,FP 12 ,FP 13 ,FP 14 ,FP 15 ,andFP 16 .
3. Transition coupling fault ( CF tr ): the state of the aggressor cell causes the fail-
ure of a transition write operation performed on the victim cell. This fault is
sensitized by a write operation on the victim cell, while the aggressor is in a
given state. Four types of transition coupling faults exist, defined as CF tr.x0/ D

˚ <x a 0; w 1 =0 v = > ,and CF tr .x1/

D ˚ <x a 1; w 0 =1 v = > where x 2 f 0; 1 g .

This covers FP 19 ,FP 20 ,FP 21 ,FP 22 .
4. Write destructive coupling fault ( CF wd ): a non-transition write operation per-
formed on the victim cell while the aggressor cell is in a given state results in a
transition of the cell itself. Four types of write destructive coupling faults exist,
defined as CF wd . xy / D ˚ <x a y v ; w y = y v = > ,wherex; y 2 f 0; 1 g . This covers

FP 17 ,FP 18 ,FP 23 ,FP 24 .
5. Read destructive coupling fault ( CF rd ): a read operation performed on the vic-
tim cell, while the aggressor cell is in a given state, destroys the data stored
in the victim. Four types of read destructive coupling faults exist, defined as

CF rd . xy / D ˚ <x a y v ;r y = y v = y v > ,wherex; y 2 f 0; 1 g . This covers FP 29 ,FP 30 ,
FP 31 ,FP 32 .
6. Incorrect read coupling fault (CFir ): a read operation performed on the vic-
tim cell returns the incorrect logic value, while the aggressor is in a given
state. Four types of incorrect read coupling faults exist, defined as CF ir . xy / D

˚ <x a y v ;r y =y v = y v > ,wherex; y

2 f 0; 1 g . This covers FP 25 ,FP 35 ,FP 26 ,

FP 36 .
7. Deceptive read destructive coupling fault (CFdr) : a read operation performed on
the victim cell returns the correct logic value and changes the contents of the
victim while the aggressor is in a given logic state. Four types of deceptive read

destructive coupling faults exist, defined as CF dr .xy/ D ˚ <x a y v ;r y = y v =y v > ,
where x; y 2 f 0; 1 g .ThiscoversFP 27 ,FP 33 ,FP 28 ,FP 34 .
The presented set of FFMs allows covering all FPs proposed in Table 6.2 , andany
test covering these FFMs is therefore able to cover all possible 2-coupling static
faults. Other sets of fault models have been presented in the literature, such as:

Idempotent coupling fault ( CF id ): a transition write operation on the aggressor
cell forces the victim in a given state: CF id .xy; w x /

D ˚ <x a y v ; w a

x = y v = > ,

where x; y 2 f 0; 1 g .

Inversion coupling fault ( CF in ): a transition write operation on the aggressor
cell flips the content of the victim cell: CF in .x; w x /

D ˚ <x a 0 v ; w a

x =1 v = > ,

x =0 v = > ,wherex 2 f 0; 1 g .

<x a 1 v ; w a