## Overview of the 74ABT373CFCQB The **74ABT373CFCQB** is a high-performance integrated circuit (IC) belonging to the **ABT (Advanced BiCMOS Technology)** family. It is an 8-bit (octal) transparent D-type latch featuring 3-state outputs, specifically designed for driving highly capacitive loads or low-impedance backplanes. --- ### Technical Specifications | Parameter | Specification | | :--- | :--- | | **Logic Family** | ABT (Advanced BiCMOS) | | **Function** | Octal D-Type Latch | | **Output Type** | 3-State (High, Low, High-Impedance) | | **Voltage Supply Range** | 4.5V to 5.5V | | **Propagation Delay** | Approx. 3.0 ns to 5.0 ns | | **Output Current** | 32mA (source) / 64mA (sink) | | **Package Type** | CQFP (Ceramic Quad Flat Pack) | | **Operating Temperature** | Military Grade (-55°C to +125°C) | --- ### Key Pin Functions 1. **D0 - D7 (Inputs):** Data inputs for the 8 individual latches. 2. **LE (Latch Enable):** When High, the latch is "transparent" (outputs follow inputs). When Low, the data is latched/stored. 3. **OE (Output Enable):** Active-low pin. When Low, outputs are active. When High, outputs enter a high-impedance state (floating). 4. **Q0 - Q7 (Outputs):** The stored or transparent data outputs. --- ### Functional Mechanics The device combines the strengths of **Bipolar** and **CMOS** technologies: * **CMOS:** Provides low power consumption at the input stages. * **Bipolar:** Provides high-speed switching and high-current drive capability at the output stages. ### Application Use Cases * **Bus Buffering:** Used to interface between microprocessors and memory or peripherals on a shared data bus. * **Data Storage:** Temporarily holding 8 bits of data during specific timing cycles. * **Military/Aerospace:** The "QB" suffix often denotes military-grade screening, making it suitable for harsh environments where reliability is critical. --- ### Internal Logic Diagram Representation ```text +-----------+ D0 ---| |--- Q0 D1 ---| |--- Q1 ... | 8-BIT | ... D7 ---| LATCH |--- Q7 | | LE --| CONTROL | OE --| | +-----------+ ```