Well,
On 03/05/2018 01:21 PM, David Lanzendörfer wrote:
BTW: I just had the enlightenment about thresholds vs. internal vs. external power supply! Of course we can just set the internal voltage to 2.8V, then we're totally fine with V_Tn=0.8V and V_Tp=-0.8V And we of course also put that rail at the Input-Pad. The only trouble will be to convert the 2.8V logic levels to the TTL 5V when emitting it at the output-pad-cell. But that's the reason why they are so fucking big and complicated usually.
Well, they get "so fucking big" while they have to drive current.. sorry for disturbing your moment of Enlightenment a little bit. Internally, we can let drive our Standard Cells by u-Amperes (and saving power of course, every switching activity means charge or discharge the capacitance behind cells). But to drive outside something like a fancy LED we need current in m-Amperes, which is at least two or three dimensions bigger. How to drive big current? By making W and L of transistors much, much bigger and really huge.
And, for changing switching levels (low Vdd < > high Vdd) there are so called level-shifter. You might been came across while have signals on PCBs which has to cross different power levels. Mainly, level shifter are just low-Drain-Source-R Transistors between both domains and are working in both directions.
So we are internally absolute free, just placing our level shifter between the core-logic and the Io-logic; there's no problem.
Yey! I got it, just while walking to the Mexian restaurant to get me some dinner. ^_^
I will put some explenations into the document.
Well, I think, this kind of essentials needs something like a side-channel. It is definitively not the stuff I would expect in the *Process*-Document. Also mentioned the IO-Level figures and explanation do you already have there. This is something I would place in a (Standard Cell and CMOS) wiki where every rookie can get the background he/she is still missing. But it does not belong to the process.
And now I will tackle SPICE! Thanks for the link!
Your are welcome