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Logic Families Overview & Comparison

This document discusses and compares different types of logic families, including RTL, DTL, HDTL, TTL, STTL, ECL, PMOS, NMOS, and CMOS. It provides details on the circuit elements, standard gates, speed, and power characteristics of each logic family. RTL uses resistors and transistors, DTL uses diodes and transistors, TTL is widely used due to its high speed and low power, STTL is faster than TTL using Schottky diodes, and ECL is the fastest but also most complex using differential amplifiers. PMOS, NMOS, and CMOS logic families use MOSFET transistors, with CMOS being faster than NMOS but

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66 views15 pages

Logic Families Overview & Comparison

This document discusses and compares different types of logic families, including RTL, DTL, HDTL, TTL, STTL, ECL, PMOS, NMOS, and CMOS. It provides details on the circuit elements, standard gates, speed, and power characteristics of each logic family. RTL uses resistors and transistors, DTL uses diodes and transistors, TTL is widely used due to its high speed and low power, STTL is faster than TTL using Schottky diodes, and ECL is the fastest but also most complex using differential amplifiers. PMOS, NMOS, and CMOS logic families use MOSFET transistors, with CMOS being faster than NMOS but

Uploaded by

karl parilla
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LOGIC FAMILIES

OBJECTIVES
• To demonstrate the operation and function of RTL(resistor
transistor logic), DTL(dode transistor logic), HDTL(high level
diode transistor logic), TTL(transistor-transistor logic), STTL
(Schottky TTL), ECL(emitter coupled logic), PMOS(p-
channel MOSFET), NMOS(n-channel MOSFET) and
CMOS(complementary metal oxide semiconductor).
• To compare different types of logic families.
RTL – RESISTOR TRANSISTOR LOGIC
• Uses resistor and transistor as
circuit elements.
• Input circuit contains resistors.
• NOR – gate, as standard
gate.
DTL – Diode Transistor Logic
• Uses diodes and transistor as
circuit elements.
• Diode gates followed by
transistors.
• NAND – gate, as the standard
gate.
HDTL – High Level DTL
• Higher power supply voltage than DTL. Usually powered by
25V instead of 5V.
• Widely used in industry where machinery cause electrical
noise and there are large power-line transients.
TTL – Transistor Transistor Logic
• Uses a multiple emitter transistor
as inputs.
• Output stage contains mostly of
transistors for driving output at
high-speed.
• NAND – gate, as standard gate.
• TTl is widely used because of its
high-speed and low-power
consumption.
STTL – Schottky TTL
Schottky Coupled Transistor Logic
• Uses schottky diode between base-collector junction of the
transistor
• Transistor are not operated in saturation region
• Faster than TTL
ECL – Emitter Coupled Logic
• Inputs are connected to
differential amplifier. The
inputs are compared to a
reference voltage.
• Transistor operates at active
and cut-off regions only.
• Fastest
PMOS Inverter
• Uses p-channel enhancement type
MOSET
• Low power consumption.
• Very high input impedance
• Lower speed compare with TTL.
NMOS Inverter
• Uses n-channel enhancement type
MOSET
• Low power consumption.
• Very high input impedance
• Lower speed compare with TTL but
faster than PMOS.
CMOS Inverter
• Uses both p-channel and n-channel MOSFET
(complementary metal-oxide semiconductor)
• Very low standby power
• Smaller
• Variable power supply
• Faster than NMOS but slower than TTL.
Summary of Logic Families
Summary of Logic Families
Summary of Logic Families
Thank You.

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