Tie-High / Tie-Low Cells

[sandusty]

tie high cell

We used logic constants in the RTL, so there will have some internal nodes tie up to logic "H' or "L". Astro could use "Tie-High Cell"s or "Tie-Low Cell"s to make the connections.

Is there anyone could tell me reasons why we do NOT connect those signals directly to the Vdd / VSS? What's the purpose of those Tie-H/L Cells? Is there any suggestions on using Tie-H/L Cells (in back end)?

 

[tom123]

tie high

using Tie-H/L Cells can provide some ESD protection for internal node.

We used logic constants in the RTL, so there will have some internal nodes tie up to logic "H' or "L". Astro could use "Tie-High Cell"s or "Tie-Low Cell"s to make the connections.

Is there anyone could tell me reasons why we do NOT connect those signals directly to the Vdd / VSS? What's the purpose of those Tie-H/L Cells? Is there any suggestions on using Tie-H/L Cells (in back end)?