The **M95640-RMB3P** is a high-performance Serial Peripheral Interface (SPI) EEPROM (Electrically Erasable Programmable Memory) manufactured by STMicroelectronics. It is designed for low-voltage applications requiring reliable non-volatile data storage. --- ### ## Technical Specifications The following table highlights the core electronic characteristics of the device: | Parameter | Specification | | :--- | :--- | | **Memory Size** | 64 Kbit (8,192 x 8 bits) | | **Interface** | SPI (Serial Peripheral Interface) | | **Max Clock Frequency** | 20 MHz (at 4.5V - 5.5V) / 5 MHz (at 1.8V) | | **Operating Voltage (Vcc)** | 1.8V to 5.5V | | **Package Type** | UFDFPN8 (Ultra-thin Fine pitch Dual Flat No-lead) | | **Endurance** | 4 Million Write Cycles | | **Data Retention** | 200 Years | | **Operating Temperature** | -40°C to +125°C | --- ### ## Key Electronic Features 1. **Low Voltage Range (R-suffix):** The "R" in the part number indicates a wide supply voltage range (1.8V to 5.5V), making it ideal for battery-powered or portable devices. 2. **SPI Modes:** It supports SPI bus modes 0 and 3, allowing for high-speed synchronous data transfer. 3. **Write Protection:** * **Hardware Protection:** A dedicated `Write Protect` ($\overline{W}$) pin. * **Software Protection:** Programmable Block Protection (Quarter, Half, or Whole memory). 4. **Byte and Page Write:** Supports writing a single byte or a full page (up to 32 bytes) in a single cycle, with a typical self-timed write cycle of 5ms. --- ### ## Pin Configuration (UFDFPN8) The device typically follows a standard 8-pin layout for SPI EEPROMs: | Pin | Symbol | Description | | :--- | :--- | :--- | | 1 | $\overline{S}$ | Chip Select (Active Low) | | 2 | Q | Serial Data Output (MISO) | | 3 | $\overline{W}$ | Write Protect | | 4 | $V_{SS}$ | Ground | | 5 | D | Serial Data Input (MOSI) | | 6 | C | Serial Clock | | 7 | $\overline{HOLD}$ | Pause Serial Communication | | 8 | $V_{CC}$ | Supply Voltage | --- ### ## Part Number Breakdown Understanding the suffix codes for **M95640-RMB3P**: * **M95640**: 64 Kbit Serial SPI EEPROM. * **-R**: Operating voltage 1.8V to 5.5V. * **MB**: UFDFPN8 package (2x3 mm). * **3**: Range 3 (Operating temperature -40 to +125 °C). * **P**: RoHS compliant / ECOPACK2 (Lead-free). --- ### ## Example Circuit Integration In a typical microcontroller application, the connections would look like this: ```cpp // Schematic Logic for SPI Connection // MCU Pin -> EEPROM Pin // GPIO -> Pin 1 (CS) // MISO -> Pin 2 (Q) // GPIO -> Pin 3 (WP) - Pull High to enable writes // GND -> Pin 4 (VSS) // MOSI -> Pin 5 (D) // SCK -> Pin 6 (C) // GPIO -> Pin 7 (HOLD) - Pull High for normal operation // 3.3V/5V -> Pin 8 (VCC) ```