The **STK14CA8-R35** is a high-performance **nvSRAM** (non-volatile Static Random Access Memory) manufactured by Infineon Technologies (formerly Cypress Semiconductor). It integrates a standard SRAM cell with a non-volatile QuantumTrap cell in a single chip. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Memory Density** | 1 Mbit (128K x 8) | | **Interface** | Parallel | | **Access Time** | 35 ns | | **Operating Voltage** | 2.7V to 3.6V | | **Package Type** | 32-pin SOIC or 48-pin SSOP | | **Data Retention** | 20 Years (at 55°C) | | **Endurance** | 1 Million STORE cycles | --- ### 2. Core Functional Components The STK14CA8-R35 is unique because it combines two types of memory technology: #### A. SRAM Cell Used for high-speed read and write operations. It behaves exactly like a standard asynchronous SRAM with a 35ns access time, allowing for unlimited read/write cycles while power is stable. #### B. QuantumTrap Cell (Non-Volatile) Every SRAM bit has a corresponding non-volatile element. When power fails, the data from the volatile SRAM is automatically transferred to the QuantumTrap cell. --- ### 3. Critical Features * **AutoStore™:** Using a small external capacitor (connected to the $V_{CAP}$ pin), the device detects power loss and automatically moves all data from SRAM to non-volatile storage without system intervention. * **Hardware Store/Recall:** Dedicated pins allow the system controller to manually trigger a data backup or restore. * **Software Store/Recall:** Sequences of specific memory addresses can be used to initiate data transfer operations via software commands. * **Infinite Read/Write:** Unlike Flash or EEPROM, the "SRAM" portion does not wear out; the endurance limit only applies to the "Store" cycles (moving data to non-volatile memory). --- ### 4. Typical Application Circuit In a standard design, the electrical integration involves: ```c // Example: Basic memory mapping in C for an MCU interface #define NV_SRAM_BASE 0x80000000 void write_data(uint32_t offset, uint8_t value) { *(volatile uint8_t *)(NV_SRAM_BASE + offset) = value; } uint8_t read_data(uint32_t offset) { return *(volatile uint8_t *)(NV_SRAM_BASE + offset); } ``` * **VCAP Pin:** Must be connected to a capacitor (usually 47µF to 100µF) to provide the energy for the AutoStore operation during power-down. * **WP (Write Protect):** Hardware protection to prevent accidental data overwrites. --- ### 5. Common Use Cases * **Industrial Controls:** Storing configuration parameters and calibration data. * **Medical Equipment:** Maintaining critical patient settings during battery failure. * **Data Loggers:** Ensuring the last recorded data point is saved if power is pulled suddenly.