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Totem Pole Transistor-Transistor Logic (TTL):.

Disadvantage of Single Output Stage TTL:.

Working of Transistor-Transistor Logic (TTL).

It is the time taken from applying the input to the output produced.

It is the amount of noise voltage allowed at the input and it should not affect the output. It is the product of the voltage which is supplied and current needed to produce the output. Number of inputs and outputs connected to the gate, which does not affect the usual performance and does not degrade the voltage. Characteristics of TTL: Fan in and Fan out: To increase the number of inputs, the number of emitters at transistor Q1 is increased accordingly.

Q3 and Q4 transistors together form the output. Transistor Q1 consists of 2 emitters, two inputs are given through this 2 emitters. It also consists of four resistors R1,R2,R3,R4 and a diode D. It consists of four transistors Q1,Q2, Q3 and Q4. This is the two input TTL NAND gate circuit. Internal Structure of 2 input NAND Gate TTL Internal structure and characteristics of standard TTL NAND gate: Logical ‘1’, input voltage required is 2V-5V.Logical ‘0’, input voltage required is 0V-0.8V.Logical ‘1’, output voltage required is 2.4V-5V.Logical ‘0’, output voltage required is 0V-0.4V.Each method and IC has advantages and disadvantages.ĭepending upon the supply voltage which is given to the IC, the voltage required to ON and OFF or to make logic ‘1’ and ‘0’ changes. Depending upon the integration of Logic families the IC number changes.

TTL Logic family ICs are in the series of 7400.

Fast TTL Input and Output levels of TTL:.

TTL is widely used because it is less expensive, more reliable and faster than the other digital logic families.ĭifferent types of Transistor- Transistor Logic are PN junction diode and resistors are also used in the integration of the chip. Transistor- Transistor Logic is made up of NPN and PNP transistor. The different types of integration of logic families are Resistor- transistor Logic (RTL), Diode- Transistor Logic (DTL), Transistor- Transistor Logic (TTL), Emitter coupled Logic (EML) and Complementary metal oxide Semiconductor Logic(CMOS). Each gate is integrated using different methods. The Logic gates which we use are manufactured using semiconductor devices like NPN and PNP transistors, Resistors, Diodes and FETs. TTL and their characteristics Transistor- Transistor Logic (TTL):