what are the inputoutput characteristics of CMOS technology

what are the input/output characteristics of CMOS technology? how are they different from TTL input/output requirements?

Solution

input/output characteristics of CMOS technology:

CMOS circuits has CMOS input.The input impedance of CMOS device is much higher usually it ranges in megohms. The CMOS input stage is controlled by the applied voltage, so there is no current flowing into the input stage. In CMOS the negative voltage peaks are limited by a protection diode. Some CMOS families input stages also have an input protection diode which is connected to VCC.

In the high state the output stage of a logic circuit of CMOS behaves like a voltage source with an open circuit voltage of 5 V. And the internal resistance for the high state is inversely proportional to the drive capability of the device. The value of the internal resistance for the standard logic families like CMOS is in the range of 30 to 40 . CMOS output stage also have an input protection diode, which is connected to VCC. This protection diode limits the positive input voltage to maximum of VCC + 0.7 V.