The **AM25LS2520DM** is a high-performance integrated circuit (IC) belonging to the Advanced Low-Power Schottky (LS) TTL family. It is specifically designed as an **8-bit Registered Arithmetic Logic Unit (ALU) Status and Control register** or, more commonly, an **Octal D-Type Latch with Three-State Outputs**. Historically manufactured by Advanced Micro Devices (AMD), this part was widely used in high-speed microprocessing units and bus-oriented architectures. --- ### 1. Key Technical Specifications | Parameter | Description | | :--- | :--- | | **Logic Family** | AM25LS (Advanced Low-Power Schottky) | | **Function** | Octal D-Type Latch (8-Bit) | | **Output Type** | 3-State (High, Low, High-Impedance) | | **Pin Count** | 22-Pin (Standard for this series) | | **Package Type** | CDIP (Ceramic Dual In-line Package) - denoted by "D" | | **Operating Temp Range** | Military Grade: -55°C to +125°C - denoted by "M" | --- ### 2. Functional Description The AM25LS2520 serves as a temporary storage element for 8 bits of data. Its primary role is to "latch" data from a bus and hold it until requested by another part of the system. #### Main Components: * **8 D-Type Latches:** These store the individual bits. * **Common Clock/Enable:** All latches operate simultaneously based on a control signal. * **Three-State Buffers:** This allows the device to be connected directly to a data bus. When the output enable is inactive, the pins enter a high-impedance state, effectively disconnecting from the bus to prevent data collisions. --- ### 3. Part Number Breakdown (Nomenclature) The suffix and prefix provide specific details about the chip's physical and electrical properties: | Segment | Meaning | | :--- | :--- | | **AM25LS** | Advanced Low-Power Schottky Technology. | | **2520** | Specific device functional code (Octal Latch). | | **D** | **Package Style:** Ceramic DIP (Dual In-line Package). | | **M** | **Temperature Grade:** Military (-55°C to +125°C). | --- ### 4. Logic Symbol Representation In a schematic, the device is represented by 8 data inputs ($D_0$ through $D_7$), 8 data outputs ($Q_0$ through $Q_7$), an Output Enable ($\overline{OE}$), and a Latch Enable ($LE$). ```text +-------+ D0 --| |-- Q0 D1 --| |-- Q1 ... | 2520 | ... D7 --| |-- Q7 | | LE --| |-- OE (Active Low) +-------+ ``` ---