The **CSTCV40M0X51Q-R0** is a surface-mount ceramic resonator manufactured by **Murata Electronics**. It is part of the CERALOCK® line, which is widely used as a cost-effective alternative to quartz crystals for clock generation in microcontrollers and other digital circuits. --- ## 1. Technical Specifications The following table summarizes the primary electrical and mechanical characteristics: | Feature | Specification | | :--- | :--- | | **Nominal Frequency** | 40.000 MHz | | **Frequency Tolerance** | ±0.5% | | **Frequency Stability** | ±0.3% | | **Resonant Impedance** | 40 Ω (Max) | | **Built-in Capacitance** | 5 pF (Internal Load Capacitors) | | **Operating Temperature** | -40°C to +125°C | | **Package Type** | SMD (Small Case Size 1206) | | **Dimensions** | 3.2 x 1.3 mm | --- ## 2. Key Internal Features ### A. Integrated Load Capacitors Unlike traditional crystals that require two external capacitors (C1 and C2) to form an oscillation circuit, the CSTCV series features **built-in load capacitors**. * **Space Saving:** Reduces the component count on the PCB. * **Reliability:** Eliminates manual matching of capacitors to the resonator. ### B. Piezoelectric Technology It utilizes the mechanical resonance of piezoelectric ceramics. When an electrical signal is applied, the ceramic material vibrates at a specific frequency (40 MHz), providing a stable clock reference. --- ## 3. Circuit Application In most microcontroller (MCU) applications, the resonator is connected to the `OSC_IN` and `OSC_OUT` pins. Because it has three terminals, the center pin is connected to Ground (GND). ```mermaid graph LR MCU_In[OSC_IN] --- Resonator_P1[Pin 1: Input] GND[Ground] --- Resonator_P2[Pin 2: Center/GND] MCU_Out[OSC_OUT] --- Resonator_P3[Pin 3: Output] ``` --- ## 4. Comparison: Ceramic Resonator vs. Quartz Crystal | Feature | Ceramic Resonator (CSTCV) | Quartz Crystal | | :--- | :--- | :--- | | **Cost** | Lower | Higher | | **Accuracy** | Moderate (±0.5%) | High (ppm levels) | | **Start-up Time** | Very Fast | Slower | | **Size** | Smaller (Integrated Caps) | Larger (External Caps needed) | **Conclusion:** Use this part if your application requires a compact, high-speed 40MHz clock where extreme precision (like high-speed USB or Ethernet timing) is not as critical as cost and space.