I know the basics in creating a schematic in CMOS, wherein in a(n inverted) boolean expression, if there is a:
- NOR - NMOS should be in parallel, PMOS in series;
- NAND - NMOS in series, PMOS in parallel.
Recently, we were tasked to do the CMOS equivalent schematic of an XOR gate. With the knowledge I have above, I came up with the schematic below having 12 transistors (including inverters, which are not shown in the figure):
I then googled if what I did was right. It was, but I saw better ones with lesser number of transistors.
This has nine:
I tried simulating the schem above and it worked.
EDIT: The third schematic doesn't work as XOR. Thank you, Curd!
This has four (I'm not sure though if it works, I haven't tried simulating it).
Question is, how do you simplify a CMOS circuit?