Design a static CMOS circuit for a 4-bit comparator circuit. The comparator circuit takes 2 bit strings as inputs, and returns the larger one. For example, for the inputs 0100 and 0011, the circuit will return 0100.
Draw the stick diagram for one comparator bit slice, and estimate all parasitic capacitances that influence the speed of the circuit. The non-linear character of capacitances is neglected.
Useful constants:
1) Overlap capacitance NMOS=0.31fF/um, PMOS=0.27fF/um.
2) Bottom junction capacitance: NMOS=2fF/um^2, PMOS=1.9fF/um^2.
3) Sidewall junction capacitance: NIMOS=0.28fF/um, PMOS=0.22fF/um.
4) Gate capacitance: NMOS=PMOS=6fF/um^2.