Design for test ,finding fault in ex-nor gate

[abhishrm]

HOW many patterns are required to test faults in EX-NOR GATE?

 

[balucyber124]

four patterns

 

[abhishrm]

It can' be 4...i think it should be 2..bt m not sure ..

 

[jeffrey samuel]

How many ip gate are u considering

Never heard of an ex-NOR gate before so do tell the IC number you are using

 

[albert22]

You must check all possible input combinations.
No matter what the function of a combinatorial digital circuit is. AND , NAND, OR, XOR, etc.
The number of input combinations is 2 to the power of number of inputs
i.e:
inputs -> comb
1 -> 2
2 -> 4
3 - > 8
4 - > 16

 

[betwixt]

I once had a whole room of engineers debating whether an XOR or XNOR gate can have more than two inputs. I think it can only have two inputs, but it certainly got some 'expert' engineers scratching their heads for a while!

Brian.

 

[abhishrm]

Let me clearify the question....number of test patterns required to test stuck at fault on 2 input EX-NOR gate?

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Its X-NOR gate ...i hope u get this nw

 

[jeffrey samuel]

The no of combinations is at all times four for a two ip gate