IC 74373 – Octal Transparent D-Type Latch with 3-State Outputs (Pack of 2)

Overview

The IC 74373 – Octal Transparent D-Type Latch is an octal transparent D-type latch with 3-state outputs, designed for use in a variety of digital applications. It is part of the 74xx series of TTL logic devices and is commonly used for data storage, buffering, and bus interfacing in digital systems.

Features

• Octal Latches: Contains eight independent transparent latches in a single package.
• 3-State Outputs: Allows multiple devices to share a common bus by enabling or disabling the outputs.
• Transparent Operation: Data passes through to the output while the latch is enabled, making it “transparent.”
• TTL Compatible: Works seamlessly with other TTL logic circuits for easy integration.
• High-Speed Operation: Capable of operating at high frequencies, suitable for fast digital systems.
• Wide Operating Voltage Range: Typically operates at 5V, standard for TTL devices.

Pin Configuration

The IC 74373 – Octal Transparent D-Type Latch is typically housed in a 20-pin Dual In-line Package (DIP). The pin configuration includes:

• Pins 1-8: Data inputs (D0-D7) for the eight latches.
• Pins 11-18: Data outputs (Q0-Q7), 3-state outputs for each latch.
• Pin 9: Output enable (OE), which controls the 3-state output buffers. When LOW, outputs are enabled; when HIGH, outputs are in high-impedance state.
• Pin 10: Latch enable (LE), controls the latching mechanism. When HIGH, the latch is transparent, allowing data to pass through; when LOW, the data is latched.
• Pin 19: Vcc (Positive Supply Voltage).
• Pin 20: Ground (GND).

Working Principle

The IC 74373 – Octal Transparent D-Type Latch operates as follows:

1. Transparent Latching: While the latch enable (LE) is HIGH, the latches are transparent, meaning the data present at the D inputs is immediately available at the Q outputs. When LE goes LOW, the data present at the D inputs at that moment is latched and held at the Q outputs.
2. 3-State Outputs: The output enable (OE) controls whether the outputs are active or in a high-impedance state. When OE is LOW, the outputs reflect the state of the latches. When OE is HIGH, the outputs are disconnected from the circuit, allowing other devices to control the bus.
3. Data Storage: The latches hold the last value present at the D inputs when the LE signal went LOW, maintaining the state until LE is enabled again.

Applications

• Data Storage: Temporarily stores data in digital circuits for processing and transmission.
• Bus Interfacing: Connects to a shared data bus, enabling multiple devices to communicate without conflicts.
• Data Synchronization: Synchronizes data between different parts of a digital system.
• Digital Systems: Commonly used in microprocessor and microcontroller circuits for data buffering and transfer.

Example Circuit

• Bus Buffering: Use the IC 74373 to buffer data between a microcontroller and a data bus. Connect the Q outputs to the bus, and control the OE pin to manage when the bus is driven by the IC. Use the LE pin to control when data is latched.

Advantages

• Versatile 3-State Outputs: Facilitates efficient bus communication, reducing the need for additional circuitry.
• High-Speed Data Handling: Supports rapid data transfer and processing, essential in modern digital systems.
• Compact Design: Integrates eight latches in a single IC, saving space and simplifying design.

Conclusion

The IC 74373 – Octal Transparent D-Type Latch is a reliable and versatile octal D-type latch with 3-state outputs, making it a valuable component in a wide range of digital applications. Its ability to transparently pass data while enabled, combined with its efficient bus interfacing capabilities, makes it ideal for use in microprocessor-based systems, data communication circuits, and digital control applications. Whether you need to buffer data or synchronize signals, the IC 74373 offers the performance and functionality needed for effective digital design.

IC 74573 – Octal D-Type Transparent Latch (Pack of 2)