What must be done to interface TTL to CMOS?
A. A dropping resistor must be used on the CMOS of 12 V supply to reduce it to 5 V for the TTL
B. As long as the CMOS supply voltage is 5 V they can be interfaced (however, the fan-out of the TTL is limited to five CMOS gates)
C. A 5 V zener diode must be placed across the inputs of the TTL gates in order to protect them from the higher output voltages of the CMOS gates
D. A pull-up resistor must be used between the TTL output-CMOS input node and Vcc; the value of RP will depend on the number of CMOS gates connected to the node
Answer:D
What must be done to interface TTL to CMOS?
A. A dropping resistor must be used on the CMOS of 12 V supply to reduce it to 5 V for the TTL B. As long as the CMOS supply voltage is 5 V they can be interfaced (however, the fan-out of the TTL is limited to five CMOS gates) C. A 5 V zener diode must be placed across the inputs of the TTL gates in order to protect them from the higher output voltages of the CMOS gates D. A pull-up resistor must be used between the TTL output-CMOS input node and Vcc; the value of RP will depend on the number of CMOS gates connected to the node
Explanation: To interface TTL to CMOS a pull-up resistor must be used between the TTL output-CMOS input node and Vcc. A pull-up resistor is used to avoid the floating state on the input node of the CMOS, thus using a small amount of current. The value of RP will depend on the number of CMOS gates connected to the node.