[Urgency] What's the difference between NAND Tree and JTAG ?

[wjccentury]

nand tree

I found in our chip nand tree and jtag both used. In my opinion, jtag is enough to test chip pins. Why we nand tree?

Who can tell me why? Thank you !!!!

 

[raju3295]

nand tree test

hi
can u briefly tell how this jtag works

 

[dft_guy]

nand tree　testとは

There may be some pins not covered in the boundary scan chain (analog, differential, etc.) and the design may have put the NAND tree in to cover those. NAND tree is OK (and quick for ATE device-level test), but for board test, JTAG is a more standard approach, and I'm sure preferred by board test engineers.

John
DFT Digest