Silly question, are there any logic processes besi...
# generalz
Zachary Curtis
08/07/2022, 7:01 PMSilly question, are there any logic processes besides CMOS that could theoretically be done on Sky130?
a
Arman Avetisyan
08/08/2022, 3:52 AMNmos only, pmos only, bipolar logic.
Obviously it has bigger area, worse power, etc
m
manili
08/08/2022, 3:02 PM@Zachary Curtis
You should build a standard cell library from scratch.
@Arman Avetisyan
But I think the bipolar version going to be faster than the CMOS version. 😄
z
Zachary Curtis
08/08/2022, 3:03 PMWhy would bipolar be faster and if so why isn't it more used?
m
manili
08/08/2022, 3:09 PMI’m not expert in this field but it could be said:
MOSFETs are slower than BJTs because of enormous capacitances at their junctions, formed by metal, substrate and the oxide layer.
But usually BJTs eat (!) a HUGE amount power which is very important factor.
There are many more details about this but I’m not a good candidate for describing those details.
manili
08/08/2022, 3:11 PMPlease note that BJTs are vastly used in analog (specifically RF) field.
p
Philipp Gühring
08/08/2022, 6:11 PMI am not sure, whether it counts as a logic process, but SONOS Flash would be another application that Sky130 provides.
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Larry Harris
08/08/2022, 7:02 PMHere is my two cents worth and a little bit of history. Bipolar Transistors (a.k.a. BJTs) was 1st mass produced silicon process. The dominate BJT logic was known as I-squared-L, or current injection logic. The transistors were always on so there was a lot of power consumed. It was quickly replaced with Cmos because the Pch
Larry Harris
08/08/2022, 7:04 PMThis was replaced with Cmos because the PCH and NCH transistors can be easily turned on and off, thus breaking the dc current path between Vdd and Gnd. Cmos logic is orders of magnitude lower power than BJT logic.
r
Rita
08/08/2022, 7:05 PMAlso the process isn't optimized for BJTs right?
Rita
08/08/2022, 7:06 PMThis isn't a BiCMOS process I believe
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Larry Harris
08/08/2022, 7:06 PMYes, the Sky130 process is not optimized for BJTs.
Larry Harris
08/08/2022, 9:23 PMMy mistake, I squared L logic, (also called IIL) stands for "Integrated Injection Logic". This is different than "Current Injection Logic", which is known as CIL.
Larry Harris
08/08/2022, 9:25 PMHere is a link to a CIL paper https://ieeexplore.ieee.org/document/1051271
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