CD74HC21E

Product Overview

• Category: Integrated Circuit
• Use: Logic Gates
• Characteristics: High-Speed CMOS, Dual 4-Input AND Gate
• Package: PDIP-14
• Essence: The CD74HC21E is a dual 4-input AND gate that belongs to the high-speed CMOS logic family. It provides a fast and efficient way to perform logical AND operations on multiple inputs.
• Packaging/Quantity: The CD74HC21E is typically sold in packs of 10 or 25 units.

Specifications

• Supply Voltage: 2V to 6V
• Logic Family: HC
• Number of Inputs: 4 per gate
• Number of Gates: 2
• Propagation Delay: 9 ns (typical)
• Operating Temperature Range: -40°C to 85°C

Pin Configuration

The CD74HC21E has a 14-pin dual in-line package (PDIP-14) with the following pin configuration:

+---+--+---+ A1 -|1 +--+ 14|- VCC B1 -|2 13|- C1 A2 -|3 12|- B2 B2 -|4 CD74HC21E 11|- A3 Y1 -|5 10|- B3 Y2 -|6 9|- A4 GND -|7 8|- B4 +----------+

Functional Features

• Dual 4-input AND gates allow for logical AND operations on four input signals simultaneously.
• High-speed CMOS technology enables fast switching times and low power consumption.
• Wide operating voltage range makes it compatible with various digital systems.
• Schmitt-trigger inputs provide hysteresis, improving noise immunity and signal integrity.

Advantages and Disadvantages

Advantages: - High-speed operation allows for efficient processing of logic operations. - Low power consumption makes it suitable for battery-powered devices. - Wide operating voltage range provides flexibility in different applications. - Schmitt-trigger inputs enhance noise immunity and signal quality.

Disadvantages: - Limited number of gates per package may require multiple ICs for complex logic circuits. - Propagation delay may introduce timing issues in certain high-frequency applications. - PDIP-14 package may not be suitable for space-constrained designs.

Working Principles

The CD74HC21E operates based on the principles of CMOS logic. It uses MOSFET transistors to implement the AND gate functionality. When all input signals are high (logic level 1), the output will be high. Otherwise, the output will be low (logic level 0). The internal circuitry ensures fast switching times and low power consumption.

Application Field Plans

The CD74HC21E can be used in various digital systems and applications, including: - Arithmetic and logical units in microprocessors and microcontrollers - Data processing and control circuits - Signal conditioning and filtering circuits - Communication systems - Industrial automation and control systems

Alternative Models

If the CD74HC21E is not available or suitable for a particular application, alternative models that offer similar functionality include: - SN74HC21N - MC74HC21AN - 74HCT21

These alternatives can be considered as drop-in replacements for the CD74HC21E, with slight variations in specifications and pin configurations.

In conclusion, the CD74HC21E is a dual 4-input AND gate integrated circuit belonging to the high-speed CMOS logic family. It offers fast switching times, low power consumption, and wide operating voltage range. Its applications range from microprocessors to communication systems. Alternative models are available for compatibility and flexibility in different designs.