load resistor

1. An NMOS inverter must drive a load capacitance of 50 fF with an output resetime of 100 ps. Assuming the risetime is given by three output time constants, determine the maximum load resistor value
2. An NMOS inverter with a load capacitance of 100 fF exhibits an output low level of 50 mV and an output risetime of 200 ps. Compute the load resistor and (W/L)1 if the risetime is given by three output time constants.