In a particular logic family, the standard inverter, when loaded by a similar circuit, has a propagation delay specified to be 0.9 ns:
(a) If the current available to charge a load capacitance is half as large as that available to discharge the capacitance, what do you expect tPLH and tPHL to be?
(b) If when an external capacitive load of 0.5 pF is added at the inverter output, its propagation delays increase by 50%, what do you estimate the normal combined capacitance of inverter output and input to be?
(c) If without the additional 0.5-pF load connected, the load inverter is removed and the propagation delays were observed to decrease by 40%, estimate the two components of the capacitance found in (b): that is, the component due to the inverter output and other associated parasitics, and the component due to the input of the load inverter.