Inverter madness - Interview Question

• The following graph plots the voltage transfer characteristic for a device with one input and one output. Can this device be used as a combinational device in a logic family with 0.75V noise margins?

• You are designing a new logic family and trying to decide on values of the four parameters V_IL, V_OL, V_IH, V_OH that lead to non-zero noise margins for various possible inverter designs. Four proposed inverter designs exhibit the voltage transfer characteristics shown in the diagrams below. For each design, either (1) specify suitable values of V_IL, V_OL, V_IH, V_OH. or (2) explain why no values for these parameters satisfy the static discipline.

Difficulty: Medium