## STK14D88-R45 Technical Overview The **STK14D88-R45** is a high-performance **256-Kbit (32K x 8) Non-volatile Static RAM (nvSRAM)** manufactured by Infineon Technologies (formerly Cypress Semiconductor). It is designed for applications requiring high-speed data access combined with the reliability of non-volatile storage. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Density** | 256 Kbit (32,768 words × 8 bits) | | **Access Time** | 45 ns | | **Interface** | Parallel (SRAM compatible) | | **Operating Voltage** | 2.7V to 3.6V (Typical 3.3V) | | **Package Type** | 32-pin SOIC (300 mil) | | **Endurance** | 1,000,000 STORE cycles | | **Data Retention** | 20 Years (minimum) | --- ### 2. Core Architecture & Operation The STK14D88 combines two distinct memory technologies into a single chip: 1. **Fast SRAM:** Provides high-speed read and write cycles (45ns). 2. **Non-volatile Element (QuantumTrap):** A shadow EEPROM cell paired with every SRAM cell. #### How it works: * **Normal Operation:** The device acts as a standard high-speed SRAM. Data is read and written using standard `CE` (Chip Enable), `OE` (Output Enable), and `WE` (Write Enable) signals. * **STORE Operation:** During a power failure or manual command, the data is transferred from the SRAM to the non-volatile elements. * **RECALL Operation:** Upon power restoration, the data is automatically copied back from the non-volatile elements into the SRAM. --- ### 3. Critical Features * **AutoStore™:** The device monitors the $V_{CC}$ level. If the voltage drops below a safe threshold, the device automatically initiates a STORE operation using charge stored in a small external capacitor ($V_{CAP}$). * **Software/Hardware Store & Recall:** Aside from automatic power-down cycles, the user can trigger data transfers via specific pin sequences or software commands. * **Infinite Read/Write Life:** Unlike standard Flash or EEPROM, the SRAM portion has no wear-out mechanism. The endurance limit only applies to the number of transfers to the non-volatile section. --- ### 4. Pin Definition (Top View) ```text +-------U-------+ VCAP | 1 32 | VCC A12 | 2 31 | A14 A7 | 3 30 | A13 A6 | 4 29 | /WE A5 | 5 28 | A8 A4 | 6 27 | A9 A3 | 7 26 | A11 A2 | 8 25 | /OE A1 | 9 24 | A10 A0 | 10 23 | /CE DQ0 | 11 22 | DQ7 DQ1 | 12 21 | DQ6 DQ2 | 13 20 | DQ5 VSS | 14 19 | DQ4 DQ3 | 15 18 | /HSB (Hardware Store Busy) +---------------+ ``` --- ### 5. Typical Applications * **Industrial Automation:** Storing configuration parameters and state machines. * **Data Loggers:** Ensuring no data is lost during sudden power interruptions. * **Medical Equipment:** Critical calibration and patient data storage. * **RAID Controllers:** Storing cache metadata.