The **7140LA55CB** is a high-speed, low-power CMOS Dual-Port Static RAM (SRAM) manufactured by IDT (Integrated Device Technology, now part of Renesas). This specific part is designed for military or high-reliability applications, as indicated by the "CB" suffix. --- ### 1. General Specifications Below are the primary technical characteristics of the 7140LA55CB: | Feature | Specification | | :--- | :--- | | **Memory Capacity** | 8K bits (1K x 8 bits) | | **Memory Type** | Dual-Port Static RAM (SRAM) | | **Access Time** | 55 ns (nanoseconds) | | **Voltage Supply** | 5V (±10%) | | **Power Consumption** | Low Power ("LA" version) | | **Package Type** | Sidebraze Dual-In-Line Package (DIP) - 48 Pins | | **Operating Temp** | Military Range (-55°C to +125°C) | --- ### 2. Key Functional Features The 7140 series is unique because it allows **asynchronous access** to the same memory location from two separate ports. * **Independent Control:** Each port (Left and Right) has its own independent Control, Address, and I/O pins. This allows for simultaneous reads or writes. * **Arbitration Logic:** It includes on-chip hardware for "Busy" logic to handle instances where both ports attempt to write to the same address simultaneously. * **Interrupt Logic:** It features semaphore signaling to allow communication between two processors using the memory space. * **Technology:** Manufactured using high-performance CMOS technology, which ensures high speed with significantly lower power consumption than traditional bipolar TTL parts. --- ### 3. Pinout Structure (High Level) The 48-pin configuration is organized to provide dual paths: 1. **Address Lines ($A_{0L} - A_{9L}$ and $A_{0R} - A_{9R}$):** Separate address inputs for left and right ports. 2. **Data I/O ($I/O_{0L} - I/O_{7L}$ and $I/O_{0R} - I/O_{7R}$):** 8-bit bidirectional data lines for each port. 3. **Control Signals:** * $\overline{CE}$: Chip Enable * $\overline{OE}$: Output Enable * $R/\overline{W}$: Read/Write Control * $\overline{BUSY}$: Hardware arbitration signal --- ### 4. Application Use Cases Because this is a "CB" grade (Ceramic Sidebraze) part, it is typically found in: * **Military Systems:** Avionics, radar processing, and guidance systems. * **Multi-Processor Systems:** Acting as a "mailbox" or buffer between two different CPUs. * **Digital Signal Processing (DSP):** High-speed data buffering between a controller and a processor.