Optical Coupling TTL To CMOS

Sunday, February 21st, 2021 - Digital

Coupling in digital circuits between TTL and CMOS systems can use the optocoupler. Optically coupling these techniques to overcome the differences between the source voltage circuits used TTL and CMOS circuits. Voltage source for TTL circuits is 5 volts. While the source voltage for CMOS circuits is 3-15VDC so there is a difference between the TTL logic levels and CMOS systems. With this optical coupling technique TTL or CMOS logic can be forwarded to the circuit with CMOS or TTL system safely and perfectly.

Optical Coupling TTL To CMOS Circuit


Above the optical coupling circuit built with optocoupler 4-pin and NOT gates, inverters or buffers on each side of the input and output. NOT gate, an inverter or a buffer used in the TTL side use of NOT gate fom TTL IC, while on the output side NOT gate CMOS using the NOT gate CMOS IC. For the application of CMOS to TTL then the coupling position TTL and CMOS NOT gate and source voltage exchanged, and the optocoupler fixed position.

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