Select of the sizes transistors.
Have next schematic
F=A·B
VDD
F
A
B
GND
Kp = 50 uA/V2, Kn = 120 uA/V2
Technology process 180 nm. Sizes for topology next:
Lp = 2λ = 180 nm.
Ln = 2λ = 180 nm.
The width will calculated from condition Irise = Ifale.
Because μn > μp, width of n-channel is minimum – 4λ
Kp · Wp/Lp = Kn · Wn/Ln
Wp = Kn /Kp· Wn/Ln · Lp
Wp = 120/50 · 4λ/2λ · 2λ = 120/50 · 4λ = 9,6λ (rounding up to the nearest
integer )=> 10λ
Sketch of topology nand2:
Contact
Metal
n+ diffusion
p+ diffusion
Poly