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Guild: wafer.space Community
Channel: 🏗️ - Designing / digital
After: 2026-05-31 11:59 p.m.
Before: 2026-07-01 12:00 a.m.
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[2026-06-03 6:37 p.m.] namibj
Having an inverter at the output of a logic cell (buffering the internal node) is almost a given, right?
So any custom gates in any static logic family I have to draw I should expect to use an inverter as an output buffer after the actual gate itself, right?


[2026-06-03 6:53 p.m.] 246tnt
Sometimes you'll find `_0` variants of gates where it's directly the internal output but yeah that's rate and not that useful for general P&R where you'd almost always have an inverter at the output ... except if the cell in question is an inverter or a delay cell .

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[2026-06-04 8:12 a.m.] chips4makers
No. CMOS standard cells have NAND2 and AOI amd OAI cells that don't have inverter at the end and these cells will be used quite a lot in the synthesized netlist.


[2026-06-07 3:30 p.m.] polyfractal
I just noticed the SRAM behavioral model has timing constraints (55.6 ns, ~18MHz). Do we know if this is a real limit of the SRAM, or just a quirk of the fab's sram model?


[2026-06-07 8:24 p.m.] rebelmike
That seems close to the 1.8V figures on https://gf180mcu-pdk.readthedocs.io/en/latest/IPs/SRAM/gf180mcu_fd_ip_sram/cells/gf180mcu_fd_ip_sram__sram512x8m8wm1/gf180mcu_fd_ip_sram__sram512x8m8wm1.html


[2026-06-07 8:24 p.m.] rebelmike
So I assume you can safely ignore at 5V or 3v3


[2026-06-07 8:39 p.m.] polyfractal
aha good catch! Didnt realize the docs had those tables for the sram 👍


[2026-06-07 8:39 p.m.] polyfractal
thanks!


[2026-06-07 9:55 p.m.] namibj
Does anyone have t_FO4 on hand by chance?


[2026-06-12 8:17 a.m.] tholin
@RebelMike @Leo Moser (mole99) Overdue update to my SCL: non-inverting latches. So you can use those now and drop any inverters you had to place in your design.
Always remember to gate-level simulate, there should be no more missing cell models now.

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[2026-06-12 8:19 a.m.] rebelmike
Awesome, thank you!


[2026-06-12 8:39 a.m.] mole99
Opened an open_pdks PR to update the hash: https://github.com/RTimothyEdwards/open_pdks/pull/525


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