The **74ABT373CPC** is a high-performance integrated circuit (IC) belonging to the **Advanced BiCMOS Technology (ABT)** family. It is an octal transparent D-type latch with 3-state outputs. --- ## 1. Core Specifications The 74ABT373 is designed for high-speed, low-power applications, combining the high drive of bipolar transistors with the low power consumption of CMOS technology. | Parameter | Value / Description | | :--- | :--- | | **Logic Family** | ABT (Advanced BiCMOS) | | **Function** | Octal Transparent D-Type Latch | | **Number of Bits** | 8-bit | | **Supply Voltage ($V_{CC}$)** | 4.5V to 5.5V | | **Output Type** | 3-State (High-Impedance capability) | | **Drive Current** | High Drive: $I_{OH}$ = -32mA / $I_{OL}$ = 64mA | | **Package Type** | PDIP-20 (Plastic Dual In-line Package) | --- ## 2. Pin Configuration and Functions The device features 20 pins, housing eight individual latches that operate simultaneously based on common control signals. | Pin Name | Description | Function | | :--- | :--- | :--- | | **$D_0 - D_7$** | Data Inputs | The 8 data bits to be latched. | | **$Q_0 - Q_7$** | Data Outputs | The stored or transparent data bits. | | **LE** | Latch Enable | Controls whether the latch is transparent or holding. | | **$\overline{OE}$** | Output Enable | Controls the 3-state outputs (Active Low). | | **GND / $V_{CC}$** | Power | Ground (Pin 10) and Supply Voltage (Pin 20). | --- ## 3. Operational Logic The 74ABT373 operates in two primary modes: **Transparent** and **Latched**. ### Truth Table | Operating Mode | $\overline{OE}$ | LE | $D_n$ | $Q_n$ | | :--- | :---: | :---: | :---: | :---: | | **Transparent** | L | H | L | L | | **Transparent** | L | H | H | H | | **Latched** | L | L | X | $Q_0$ (Previous State) | | **High-Z** | H | X | X | Z (High Impedance) | --- ## 4. Key Features * **High Speed:** Typical propagation delays of approximately 3.0ns to 5.0ns. * **Non-Inverting Outputs:** The outputs ($Q$) match the logic state of the inputs ($D$). * **Bus-Oriented:** The 3-state outputs allow the chip to be connected directly to system buses (like a microprocessor data bus) without interference. * **Power-Up/Down High Impedance:** Specifically designed to prevent "glitches" or bus contention during power cycling. --- ## 5. Typical Applications * **Temporary Data Storage:** Used to hold data from a bus while the processor performs other tasks. * **I/O Port Expansion:** Adding more output lines to a microcontroller. * **Bus Interfacing:** Buffering signals between different parts of a digital system to maintain signal integrity and drive strength.