Scan Chain Test Pattern of ATPG tool

[kiranks9]

Scan Chain Test Pattern

All
ATPG tool generates the chain test pattern in the form "001100", why is it so? what is signifcance? why cant generate the 0101010 or "000111000" or other pattern

Kiran KS

 

[ebuddy]

Pattern is generated based on the ATPG algrithm. Depending on the DUT logic, the pattern will trigger certain nodes and let you measure the result against the predicated result.

 

[luwanzen]

This sequence produces all four transitions, 0->0,0->1,1->1,and 1->0, in each flip-flop.

 

[gemini_77]

kindly through more light on the requirement of 0->0 & 1->1
what is the defect that will be covered by the above sequnence

Thanks in advance
Gem

 

[jayTudu]

The scan chain patterns are needed to be shifted in during scan initializatio operation. So if the patterns are of 0->0 or 1->1 form then there will be no toggling during the shift operation, where as if the patterns are of 01010 then there will be maximum toggling. These toggling are not good for power consumption. Means if there will be more toggling then more dynamic power will be consumed.
Hope this answers your question.

With regards,
Jaynarayan

 

[Pravith]

Please let me know how this pattern (0011) helps in timing check (hold time) of scan chains.