Isolation cells (hold recent value?)

[oak_tree]

Hi all,

In some reference books it is mentioned that there are 3 types of isolation cells: Those that clamp the signal to '0', those that clamp the signal to '1' and those that latch it to the most recent value.

We are using 65nm TSMC library, low power (tcbn65lphvt). I can see just the isolation cells that clamp the value to '0' and to '1'. I don't see the 3rd type.

- Did I miss it? Does anyone use the same library or similar TSMC library and have those cells?

- Do those cell exist, or are they just "on paper"? Can you please check the library you use and comment.

Thanks in advance.

 

[vlsichipdesigner]

hi,

my 2 cents,

if i understand correctly, these are State retention Cells, which register the previous values, because control registers values are required to be preserved as need basis, to perform analysis and use that data.

hope it is useful

myprayers,
chip design made easy
https://www.vlsichipdesign.com