## IDT7140LA55P: Electronic Specifications and Details The **IDT7140LA55P** is a high-speed, low-power **Dual-Port Static RAM (SRAM)**. It is designed to allow two independent processors or buses to access the same memory space simultaneously without interference, making it ideal for communication between CPUs or as a buffer. --- ### 1. Key Technical Specifications Below are the primary electronic characteristics of the IDT7140LA55P: | Parameter | Specification | | :--- | :--- | | **Memory Type** | Dual-Port Static RAM (SRAM) | | **Capacity** | 8 Kbit (1K x 8-bit) | | **Access Time** | 55 ns (Nanoseconds) | | **Interface** | Parallel | | **Voltage Supply** | 4.5V to 5.5V (Standard 5V) | | **Operating Current** | 160 mA (Active), 5 mA (Standby) | | **Package Type** | PDIP-48 (Plastic Dual In-line Package) | | **Temperature Range** | 0°C to +70°C (Commercial) | --- ### 2. Part Number Breakdown The part number follows a specific nomenclature used by Integrated Device Technology (now part of Renesas): * **IDT7140**: The base model number for a 1K x 8 Dual-Port RAM. * **LA**: Low Power version. * **55**: Access time of 55 nanoseconds. * **P**: Plastic Dual In-line Package (PDIP). --- ### 3. Functional Features The "Dual-Port" nature of this chip introduces specific electronic logic for managing data: 1. **Independent Control**: It features two completely independent ports (Left and Right) with their own control, address, and I/O pins. 2. **Arbitration Logic**: It includes "Busy" logic signals to handle situations where both ports attempt to write to the same memory location at the exact same time. 3. **Interrupt Flags**: It provides a semaphore/mailbox system via interrupt flags to allow one side of the memory to signal the other side that data is ready. 4. **No Clock Required**: As an asynchronous SRAM, it does not require a system clock to operate; timing is controlled by the Address and Chip Enable signals. --- ### 4. Typical Application Circuit In a digital system, the IDT7140LA55P acts as a bridge. Below is a conceptual representation of how it is connected: ```text [ Processor A ] <-----> [ Port L (IDT7140) Port R ] <-----> [ Processor B ] | | | | (Address A) --------> [Addr L] [Addr R] <-------- (Address B) (Data A) <----------> [Data L] [Data R] <----------> (Data B) (Control A) --------> [Ctrl L] [Ctrl R] <-------- (Control B) ``` --- ### 5. Hardware Pins Overview The PDIP-48 package includes the following pin groups: * **A0L - A9L / A0R - A9R**: Address inputs for Left and Right ports. * **I/O0L - I/O7L / I/O0R - I/O7R**: Data Input/Output lines. * **CE (Chip Enable)**: Activates the specific port. * **OE (Output Enable)**: Controls the data buffers for reading. * **R/W (Read/Write)**: Determines the direction of data flow. * **BUSY**: Output signal to indicate a port access conflict.