1. TTL BHAGWAN MAHAVIR COLLEGE OF ENGINEERING AND TECHNOLOGY, SURAT
SUBJECT : D.E ( )
GUIDED BY : Ms. HENAL PATEL
Date of submission:
PRESENTED BY : Patel Jinal S.
ENROLLMENT NO :
SEMESTER:3rd
COMPUTER SCIENCE & ENGINEERING
BMCET 1 1

2. Logic Families
We have seen that different devices use different voltages ranges for their logic levels
They also differ in other characteristics
In order to assure correct operation when gates are interconnected they are normally produced in families
The most widely used families are:
complementary metal oxide semiconductor (CMOS)
transistor-transistor logic (TTL)
emitter-coupled logic (ECL) 2

3. Introduction
TTL was developed in 1965.Through the years basic TTL has been improved to meet performance requirements. There are many versions or families of TTL. For example
High Speed TTL (twice as fast, twice as much power)
Low Power TTL (1/10 the speed, 1/10 the power of “standard" TTL)
Schottky TTL etc. (for high-frequency uses )
TTL logic families have three configurations for outputs
Totem pole output
Open collector output
Tri state output 3

4. Fig. TTL NAND gate circuit diag.[1]
Two input TTL NAND gate
Fig. TTL NAND gate circuit diag.[1] 4

5. TTL Logic State AnalysisB Q1 Q2 Q3 Q4 Y ON
OFF 1 5

6. Advantage of totem pole Low power dissipation
Fast switching 6

7. Tri-state(3-state)TTL
Fig. Tri-state TTL circuit diag.[1] 7

8. Tri-state (3-state) TTL Truth table
EN (Enable input)
IN (A)
Y (output) X
HI-Z 1 8

9. TTL sub families Standard TTL ,74 series Low power TTL , 74L series
High speed TTL , 74H series 9

10. References
[1] A . Anand Kumar, “Fundamentals of Digital Circuits”, Pp: , PHI India, June 2011. 10

11. THANK YOU
4/22/2018 11