INTRODUCTION TO LOGIC FAMILIES What is a logic Family It is the way to describe the internal circuitry of the I.C. Types of logic Families We have 7 Basic Logic Families 1) RTL – Resistor Transistor Logic 2) DTL – Diode Transistor Logic 3) IIL – Integrated injection Logic 4) TTL – Transistor – Transistor Logic (Ex 7400 & 5400 Series) 5) ECL – Emitter Coupled Logic (Ex 10000 series) 6) MOS – Metal Oxide Semiconductor 7) CMOS – Complementary Metal Oxide Semiconductor (Ex. 4000 Series) Presentation By Anant Shrivastava (E.I. Fourth Sem)

What is a logic Family

It is the way to describe the internal circuitry of the I.C.

Types of logic Families

We have 7 Basic Logic Families

1) RTL – Resistor Transistor Logic

2) DTL – Diode Transistor Logic

3) IIL – Integrated injection Logic

4) TTL – Transistor – Transistor Logic (Ex 7400 & 5400 Series)

5) ECL – Emitter Coupled Logic (Ex 10000 series)

6) MOS – Metal Oxide Semiconductor

7) CMOS – Complementary Metal Oxide Semiconductor

(Ex. 4000 Series)

RTL & DTL – Not used in new design But act as a useful starting point RTL was the first Commercial Family DTL is now Completely replaced by TTL TTL – It is a modified form of DTL it is formed by replacing each diode with a transistor Basic Gate is NAND IIL,MOS – Used in Large Scale Integration ECL – Used in High Speed Operations Basic Gate is NOR CMOS – Where power requirement is low Basic Gate is inverter Some Information on each Logic Family Presentation By Anant Shrivastava (E.I. Fourth Sem)

RTL & DTL – Not used in new design

But act as a useful starting point

RTL was the first Commercial Family

DTL is now Completely replaced by TTL

TTL – It is a modified form of DTL

it is formed by replacing each diode with a transistor

Basic Gate is NAND

IIL,MOS – Used in Large Scale Integration

ECL – Used in High Speed Operations

Basic Gate is NOR

CMOS – Where power requirement is low

Basic Gate is inverter

Characteristics Fan-out – Maximum number of standard load a gate can drive without disparity Power Dissipation – Power Required to operate the gate Expressed in mW. Propagation Delay – Time taken by the signal to propagate from input to output when a signal change occur Noise Margin – Maximum Noise voltage that can be added to circuit without unwanted effect on output (Two Types : - AC & DC Noise) Represented in V and represent max level Presentation By Anant Shrivastava (E.I. Fourth Sem)

Fan-out – Maximum number of standard load a gate can drive without disparity

Power Dissipation – Power Required to operate the gate

Expressed in mW.

Propagation Delay – Time taken by the signal to propagate from input to output when a signal change occur

Noise Margin – Maximum Noise voltage that can be added to circuit without unwanted effect on output

(Two Types : - AC & DC Noise)

Represented in V and represent max level

Common Logic Levels Characteristic Table Presentation By Anant Shrivastava (E.I. Fourth Sem) 0 0 - 0.5 V DD V DD V DD = 3 – 10 CMOS -1.8 -1.9 – -1.6 -0.8 -0.95 – -0.7 V EE = -5.2 ECL 0.2 0 - 0.4 3.5 2.4 – 5 V cc = 5 TTL Typical Range Typical Range Low Level Voltage High Level Voltage Voltage Supply Family Type 3 25 0.1 50 CMOS 0.2 2 25 25 ECL 0.4 10 2 20 Low power Schottky TTL 0.4 3 22 10 Schottky TTL 0.4 10 10 10 TTL Noise Margin Propagation delay aPower Dissipation Fan-out Family