Minimum number of scan chain in a design

SCAN, Boundary SCAN, MBIST, ATPG, JTAG, ATE, DFT simulations.
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Vijay
Posts: 25
Joined: Sun Apr 13, 2014 1:39 pm
Location: Bangalore, India

Minimum number of scan chain in a design

Post by Vijay » Tue Apr 15, 2014 11:57 am

Can we have only one scan chain in a Design?

RENU
Posts: 22
Joined: Mon Apr 07, 2014 11:18 pm

Re: Minimum number of scan chain in a design

Post by RENU » Wed Apr 23, 2014 2:47 pm

Minimum number of scan chains in a design can be decided by following factors :-

1. Number of Input - Output ports which can be use for Scan -In /Scan -out .
2. Whether you want to insert CODEC(Compresssor -Decompressor) / Serializer in your design.
3. Scannable flops in your design .


Simply , Minimum number of scan -chains = Total number of scannable flops/ Number of scan -in or scan -out ports.

So, Logically , You can have single scan chain depending upon input-output ports in your design but practically it is not recommended as your tester time will increase and hence design cost.

mbsheth
Posts: 4
Joined: Thu May 15, 2014 2:07 pm

Re: Minimum number of scan chain in a design

Post by mbsheth » Thu May 15, 2014 5:52 pm

Minimum number of scan chain is totally depends on Design.
e.g. If design can support 2 to 3 chains, thn it helps in test time reduction. If we have 1 scan chain, thn we have more test time which is not mostly preferable in current industry as design is too large and also high complexity.
So all this architectural level decision is mostly depends on design and tester support.
Hope it helps.

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Regards,
Maulin

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