How many mA are required for a LOW and HIGH signal on a digital CMOS gate.?

Question

I am looking at the datasheet for a digital XOR gate,
http://www.fairchildsemi.com/ds/NC/NC7SZ86.pdf . How many mA must be
applied to the signal pins to make a LOW or HIGH signal?

Answer 1

A CMOS gate is made with an insulator. That is why the data sheet does not list a current or resistance for the gate. The only thing important for a CMOS gate is the gate capacitance, which can determine the rise and fall time of the driving signal. This is why CMOS circuits draw very little power when nothing is changing and then draw more power as the frequency of operation goes up.

Answer 2

The input of CMOS gates is a FET transistor, hence, it does NOT require current (well microamps if we have to be tatti!).
It is the voltage difference between the substrate (ground of the chip) and the input voltage.
Low is below 1.5V, High is above 2.4V (for standard CMOS gates, series 74HCsomething.

Answer 3

The impedience is in the 100 meg ohm range so not many. The best way to find out exactly is to find the spec sheet for the part using yahoo. just do a yahoo search on the part number

Answer 4

CMOS are voltage controlled devices. An attempt to trigger them with a specific current would be error prone and dissapointing. No two would be alike.

Answer 5

4mA and 24mA. Usually this values are applied.
4mA=0%CO
12mA=50%CO
18mA=75%CO
24mA=100%CO