CD74HCT191E

Product Overview

• Category: Integrated Circuit
• Use: Counter
• Characteristics: High-Speed, CMOS Logic, Synchronous Operation
• Package: DIP (Dual In-Line Package)
• Essence: The CD74HCT191E is a 4-bit synchronous up/down counter that operates on high-speed CMOS logic. It can be used in various applications where counting and control functions are required.
• Packaging/Quantity: The CD74HCT191E is typically sold in tubes or reels, with a quantity of 25 units per tube/reel.

Specifications

• Supply Voltage: 2V to 6V
• Operating Temperature Range: -40°C to +85°C
• Logic Family: HCT (High-Speed CMOS)
• Number of Bits: 4
• Counting Modes: Up, Down, Up/Down
• Clock Input: Synchronous
• Output Type: TTL Compatible

Detailed Pin Configuration

The CD74HCT191E has a total of 16 pins, which are assigned specific functions as follows:

1. CP (Clock Pulse) - Clock input for counting operation.
2. MR (Master Reset) - Active low input used to reset the counter.
3. U/D (Up/Down) - Determines the counting direction (high for up, low for down).
4. PE (Parallel Enable) - Active high input used to enable parallel loading of data.
5. PL (Parallel Load) - Active high input used to load data into the counter.
6. Q0-Q3 (Outputs) - Four output pins representing the binary count value.
7. TC (Terminal Count) - Output pin that goes high when the counter reaches its maximum or minimum count value.

Functional Features

• Synchronous Operation: The CD74HCT191E performs counting operations synchronously with the clock input, ensuring accurate and reliable counting.
• Up/Down Counting: The counter can be configured to count up, count down, or alternate between up and down counting modes based on the U/D input.
• Parallel Loading: The counter can be loaded with a specific count value in parallel using the PL and PE inputs.
• Terminal Count Output: The TC output provides a signal indicating when the counter has reached its maximum or minimum count value.

Advantages and Disadvantages

Advantages: - High-speed operation due to CMOS technology. - Versatile counting modes for various applications. - Synchronous operation ensures accurate counting. - Parallel loading capability for easy initialization.

Disadvantages: - Limited number of bits (4 bits) may not be sufficient for certain applications requiring larger counters. - Requires an external clock source for counting operation.

Working Principles

The CD74HCT191E operates based on synchronous counting principles. When the clock pulse (CP) is applied, the counter increments or decrements its count value based on the selected counting mode (up, down, or up/down). The count value is stored in the Q0-Q3 output pins, representing the binary equivalent of the count. The counter can be reset using the master reset (MR) input, and a specific count value can be loaded in parallel using the parallel load (PL) and parallel enable (PE) inputs.

Detailed Application Field Plans

The CD74HCT191E can be used in various applications that require counting and control functions. Some potential application fields include:

1. Digital Frequency Counters: The CD74HCT191E can be utilized as a building block in digital frequency counters to accurately measure the frequency of input signals.
2. Industrial Automation: It can be employed in industrial automation systems for counting and control tasks, such as monitoring production line operations or controlling machinery.
3. Traffic Control Systems: The counter can be used in traffic control systems to keep track of vehicle movements, signal timing, or intersection control.
4. Event Counters: It can be utilized in event counters for applications like attendance tracking, inventory management, or ticketing systems.

Detailed and Complete Alternative Models

1. CD74HCT192E: Similar to the CD74HCT191E, but with a different pin configuration.
2. CD74HCT193E: A 4-bit synchronous up/down counter with separate clock inputs for up and down counting modes.
3. CD74HCT390E: A dual 4-bit decade counter that can count up to 99 in decimal.

These alternative models provide similar functionality to the CD74HCT191E and can be considered as alternatives based on specific requirements.

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