The **STK14D88-R35** is a high-performance **256Kbit (32K x 8) Non-Volatile Static RAM (nvSRAM)** manufactured by Cypress Semiconductor (now part of Infineon Technologies). It combines the high speed of an SRAM with the non-volatile data retention of an EEPROM. --- ### ## Technical Specifications | Parameter | Specification | | :--- | :--- | | **Density** | 256 Kbit (32,768 words × 8 bits) | | **Access Time** | 35 ns | | **Operating Voltage** | 3.0V to 3.6V (3.3V Nominal) | | **Interface** | Parallel (Standard SRAM interface) | | **Package Options** | 32-pin SOIC or 32-pin CDIP | | **Retention** | 20 Years (at 55°C) | | **Endurance** | 1 Million STORE cycles | --- ### ## Key Architectural Features 1. **Hybrid Technology**: Each memory cell consists of two components: * **SRAM Cell**: Used for high-speed read/write operations during normal powered use. * **Non-volatile Element**: A QuantumTrap storage cell that mirrors the SRAM. 2. **AutoStore Operation**: The device monitors the power supply ($V_{CC}$). If power falls below a specific threshold, the chip automatically transfers all data from the volatile SRAM to the non-volatile elements using charge stored in an external capacitor. 3. **Hardware & Software STORE/RECALL**: * **Hardware RECALL**: On power-up, the device automatically restores data from the non-volatile cells back to the SRAM. * **Software Commands**: Specific address sequences can trigger a manual STORE or RECALL operation. --- ### ## Pin Functionality Below is a simplified view of the primary control pins for the STK14D88: | Pin Name | Function | Description | | :--- | :--- | :--- | | **A0 - A14** | Address Inputs | Selects one of the 32,768 bytes. | | **DQ0 - DQ7** | Data I/O | Bidirectional data bus. | | **$\overline{CE}$** | Chip Enable | Activates the device. | | **$\overline{WE}$** | Write Enable | Enables writing to the SRAM. | | **$\overline{OE}$** | Output Enable | Enables data output during a read. | | **$V_{CAP}$** | Capacitor Pin | Connection for the AutoStore energy storage capacitor. | --- ### ## Applications The STK14D88-R35 is typically used in industrial and critical systems where data loss is unacceptable: * **Medical Equipment**: Storing calibration data and patient logs. * **Industrial Automation**: Storing PLC state information and configuration. * **Networking**: Storing routing tables or error logs during power failure. * **Smart Meters**: Retaining billing data. ---