Comparison between various digital logic families

Parameter	RTL	DTL	TTL	ECL	CMOS
Components used	Resistor and transistor	Resistor, diode and transistor	Resistor, diode and transistor	Resistor and transistor	N-channel and P-channel MOSFET
Circuit	Simple	Moderate	Complex	Complex	Moderate
Noise margin	Nominal	Good	Very good	Good	Very good
Fan-out	Low	Medium	Medium	High	-
Power dissipation	12	8-12	10	40-55	0.1
Basic gate	NOR	NAND	NAND	NOR-OR	NAND/NOR
Propagation delay	12	30	10	2	70
Speed power product	144	300	100	100	0.7
Application	Absolute	Absolute	Lab instrument	High speed switching application	Portable instrument where battery supply is used.
Number of function	High	Fairly High	Very high	High	Low
Clock rate	8	12-30	15-60	60-400	5

 

Digital logic circuit

Unit 1

Representation of number of different Radix

Conversion of number system

Binary Arithmetic

Binary codes

Error detection and correction codes

Characteristics of digital logic families

RTL

DTL

TTL

MOS Families

ECL

Comparison between families