Q. What must be done to interface TTL to CMOS? (Solved)
1. a dropping resistor must be used on the cmos 12 vsupply to reduce it to 5 v for the ttl.
2. 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.
3. 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.
4. a pull-up resistor must be used between the ttl output- cmosinput node and vcc; the value of rp will depend on the number of cmosgates connected to the node.
- d. a pull-up resistor must be used between the ttl output- cmosinput node and vcc; the value of rp will depend on the number of cmosgates connected to the node.