The **CSTCE19M6V51-R0** is a ceramic resonator from the **CERALOCK®** line manufactured by **Murata Electronics**. It is a surface-mount device (SMD) used primarily for generating clock signals in microcontrollers and other digital circuits. --- ## 1. Technical Specifications The part number encodes specific technical details about its operation: | Parameter | Specification | | :--- | :--- | | **Nominal Frequency** | 19.66 MHz | | **Frequency Tolerance** | ±0.5% | | **Frequency Stability** | ±0.3% (over temperature) | | **Operating Temperature** | -20°C to +80°C | | **Built-in Capacitance** | 5pF (Internal load capacitors) | | **Package Size** | 3.2 x 1.3 mm (Small Cap type) | | **Mounting Type** | Surface Mount (SMD) | --- ## 2. Key Internal Components Unlike a simple quartz crystal, this ceramic resonator is a "three-terminal" device. It integrates the following components into a single package: 1. **Piezoelectric Ceramic Element:** The core that vibrates at the 19.66 MHz frequency when stimulated by an electric field. 2. **Internal Load Capacitors:** It contains two 5pF capacitors connected to the ground pin. This eliminates the need for external capacitors on the PCB, saving space and reducing BOM (Bill of Materials) costs. 3. **Alumina Substrate:** The base material that provides mechanical support and thermal stability. --- ## 3. Circuit Application In a typical microcontroller (MCU) circuit, the resonator is connected to the `OSC_IN` and `OSC_OUT` pins. Because it has built-in capacitors, the middle pin is simply connected to the System Ground (GND). ```mermaid graph LR MCU_OSC_IN --- Pin1[Input] GND --- Pin2[Ground] MCU_OSC_OUT --- Pin3[Output] ``` ### Advantages vs. Quartz Crystals * **Cost:** Generally cheaper than quartz crystals. * **Size:** Smaller footprint due to integrated capacitors. * **Startup Time:** Faster oscillation startup time compared to crystals. * **Durability:** Highly resistant to mechanical vibration and shock. --- ## 4. Common Use Cases This specific frequency (19.66 MHz) is often chosen because it is a multiple of standard baud rates, making it ideal for: * **High-speed UART communication** (RS-232/RS-485). * **Microcontrollers** (AVR, PIC, or ARM) requiring a stable external clock. * **Consumer Electronics** such as remote controls and small appliances.