Digital Electronics - Chapter 3: Logic Gates, Logic Circuits and Digital Integrated Circuits - Lê Dũng

and Telecommunications Page 13
3.1 LOGIC GATES
9Logic Gates in Small Scale Integrated IC
Quadruple 2-Input And-gates IC 7408 AND gate
TTL AND gate circuit
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3.1 LOGIC GATES
9Logic Gates in Small Scale Integrated IC
Quadruple 2-Input OR-gates IC 7432 OR gate
TTL OR gate circuit
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3.1 LOGIC GATES
9Logic Gates in Small Scale Integrated IC
Quadruple 2-Input NAND-gates IC 7400 NAND gate
TTL NAND gate circuit
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3.1 LOGIC GATES
9Logic Gates in Small Scale Integrated IC
Quadruple 2-Input NOR-gates IC 7402 NOR gate
TTL NOR gate circuit
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3.1 LOGIC GATES
9Logic Gates in Small Scale Integrated IC
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3.2 LOGIC CIRCUITS
9 Principles of Logic Gate Connection
The rules of connection ?.
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3.2 LOGIC CIRCUITS
9 Principles of Logic Gate Connection
e.g. TTL output connects to CMOS input 
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3.2 LOGIC CIRCUITS
9 Principles of Logic Gate Connection Æ the rules
+ Must be compatible in logic level
+ One output can control more than one input
+ Two or more outputs usually should not be 
connected together.
+ Don’t let a input as a floating input. 
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3.2 LOGIC CIRCUITS
9Two models of Logic Circuits
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3.2 LOGIC CIRCUITS
9 Synthesis and Analysis Logic Circuits
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3.2 LOGIC CIRCUITS
9Active Level (Asserted level)
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3.2 LOGIC CIRCUITS
9Active Level Conversion
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3.2 LOGIC CIRCUITS
9Alternated Logic Gates (active level conversion) 
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3.2 LOGIC CIRCUITS
9Active level conversion to make a compatible in 
logic circuits
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3.2 LOGIC CIRCUITS
9Exercises 1: active level conversion 
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3.2 LOGIC CIRCUITS
9Exercises 2: active level conversion 
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3.3 DIGITAL INTEGRATED CITCUITS
9 Integrated Circuit ?. 
An integrated circuit (also referred to as IC, chip, or 
microchip) is an electronic circuit manufactured by 
lithography
All logic gates, logic circuits Æ implemented on a single chip Æ Digital ICs
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3.3 DIGITAL INTEGRATED CITCUITS
9Lithography for integrated circuit fabrication
Pattern 
transfer
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3.3 DIGITAL INTEGRATED CITCUITS
9 Scale of Integration
SCALE OF INTEGRATION NUMBER OF GATES APPLICATION 
SSI 
Small-Scale Integrated 
 < 12 “Off-the-shelf” IC for basic logic gate and Flip-flop 
MSI 
Medium-Scale Integrated 
12 ~ 99 “Off-the-shelf” IC Decoder, Encoder, Mux, Counter, 
Shift registers 
LSI 
Large-Scale Integrated 
VLSI 
Very-Large-Scale Integrated 
ULSI 
Ultra-Large-Scale Integrated 
100 ~ 9999 
10.000 ~ 99.999 
> 100.000 
A digital system, such as digital clock, calculator, 
memory RAM ROM, PROM, EPROM, Flash, 
Microcontroller, Microprocessors, System on 
Chip  
 * Giga-scale integration(GSI)1,000,000 or more(109 - 1011)
* Tera-scale integration(TSI) (1012 or more)
Moore’s Law: The number of components that can be packed on a 
computer chip doubles every 18 months while price stays the same.
1.2 Billion individual 
transistor gates onto the 
Quad-core i7-2700k 
"Sandy Bridge" 64-bit 
microprocessor chip
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3.3 DIGITAL INTEGRATED CITCUITS
9Most of the reasons that modern digital systems 
use integrated circuits
™IC pack a lot more circuitry in a small package Æ the 
overall size of any digital system is reduced.
™IC have made digital systems more reliable by reducing 
the number of external interconnections.
™IC typically requires less power than their discrete 
counterpartsÆ saving in power and a system does not 
require as much cooling
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3.3 DIGITAL INTEGRATED CITCUITS
9Logic Families
DL : Diode Logic.
RTL : Resistor Transistor Logic.
DTL : Diode Transistor Logic.
HTL : High Threshold Logic.
TTL : Transistor Transistor Logic.
I2L : Integrated Injection Logic.
ECL : Emitter Coupled Logic.
MOS : Metal Oxide Semiconductor Logic (PMOS and NMOS).
CMOS : Complementary Metal Oxide Semiconductor Logic.
BiCMOS : Combines bipolar and CMOS devices into single integrated circuit.
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3.3 DIGITAL INTEGRATED CITCUITS
9Digital IC notation
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3.3 DIGITAL INTEGRATED CITCUITS
9DL, RTL, DTL, HTL structures 
DTL - NAND gate
Diode logic
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3.3 DIGITAL INTEGRATED CITCUITS
9 IIL structures 
- Integrated injection logic (IIL, I2L, or I2L) is a class of digital circuits built 
with multiple collector bipolar junction transistors (BJT)
- When introduced it had speed comparable to TTL yet was almost as 
low power as CMOS, making it ideal for use in VLSI (and larger) 
integrated circuits.
- Although the logic voltage levels are very close (High: 0.7V, Low: 0.2V), 
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3.3 DIGITAL INTEGRATED CITCUITS
9ECL structures 
- A high-speed integrated circuit bipolar transistor logic family. 
- ECL uses an overdriven BJT differential amplifier with single-ended 
input and limited emitter current to avoid the saturated (fully on) 
region of operation and its slow turn-off behavior
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3.3 DIGITAL INTEGRATED CITCUITS
9The structure of standard TTL NAND Gate: 
Multiple emitter and Totem pole 
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3.3 DIGITAL INTEGRATED CITCUITS
9The operation of standard TTL NAND gate
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3.3 DIGITAL INTEGRATED CITCUITS
9The operation of standard TTL NAND gate
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3.3 DIGITAL INTEGRATED CITCUITS
9Tri-state or Hi-Z output of TTL gate 
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3.3 DIGITAL INTEGRATED CITCUITS
9Tri-states output application 
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3.3 DIGITAL INTEGRATED CITCUITS
9Open collector output of TTL gate 
Wired-OR circuits
Different voltage Interfacing
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3.3 DIGITAL INTEGRATED CITCUITS
9 Structure of Low-power Schottky TTL 
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3.3 DIGITAL INTEGRATED CITCUITS
9 Structure of NMOS gate 
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3.3 DIGITAL INTEGRATED CITCUITS
9 Structure of CMOS gate 
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3.3 DIGITAL INTEGRATED CITCUITS
9 Specifications of Digital IC
¾ Current & Voltages
¾ Fan-out, Fan-in 
¾ Propagation Delay
¾ Noise Margin
¾ Power Dissipation
¾ Speed Power Product
From Datasheet
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3.3 DIGITAL INTEGRATED CITCUITS
9 Specifications of Digital IC
¾ Voltages and Noise Margin
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3.3 DIGITAL INTEGRATED CITCUITS
9 Specifications of Digital IC
¾ Currents & Fan-out, Fan-in
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3.3 DIGITAL INTEGRATED CITCUITS
9 Specifications of Digital IC
¾ Currents of the logic families
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3.3 DIGITAL INTEGRATED CITCUITS
9 Specifications of Digital IC
¾ Propagation Delay
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3.3 DIGITAL INTEGRATED CITCUITS
9 Specifications of Digital IC
¾ Propagation delay of the TTL and CMOS families
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3.3 DIGITAL INTEGRATED CITCUITS
9 Specifications of Digital IC
¾ Power Dissipation and Speed-Power Product
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3.3 DIGITAL INTEGRATED CITCUITS
9 Specifications of Digital IC
¾ Speed and power dissipation of TTL and CMOS families 
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3.3 DIGITAL INTEGRATED CITCUITS
9TTL and CMOS connections
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3.3 DIGITAL INTEGRATED CITCUITS
9TTL and CMOS connections (cont.)
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3.3 DIGITAL INTEGRATED CITCUITS
9TTL and CMOS connect to LED
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3.3 DIGITAL INTEGRATED CITCUITS
9TTL and CMOS connect to a push button or a relay