The part number **I640-63BC9O2-155.520** refers to a high-precision **Voltage Controlled Crystal Oscillator (VCXO)** typically manufactured by specialized frequency control companies like ILSI or MtronPTI. Below is a detailed breakdown of the electronic specifications and the nomenclature for this specific component. --- ### 1. Component Overview This device is a surface-mount (SMD) timing component designed for telecommunications and high-speed networking equipment. Its primary function is to provide a stable reference clock signal at a specific frequency. ### 2. Technical Specifications Table | Feature | Specification | Description | | :--- | :--- | :--- | | **Primary Frequency** | 155.520 MHz | Standard frequency for SONET/SDH applications. | | **Component Type** | VCXO | Voltage Controlled Crystal Oscillator. | | **Output Type** | LVPECL / LVDS | Typically high-speed differential logic (often 6-pad). | | **Supply Voltage** | 3.3V (Typical) | Common logic supply voltage. | | **Package Size** | 5.0 x 7.0 mm | Standard 6-pad ceramic SMD package. | | **Frequency Stability** | ±20ppm to ±50ppm | Variation allowed over temperature. | | **Operating Temp** | -40°C to +85°C | Industrial grade temperature range. | --- ### 3. Part Number Breakdown (Nomenclature) While different manufacturers vary slightly, the "I640" series generally follows this logic: * **I640**: Series designator (indicates the physical package size, usually **5x7mm**, and the circuit type). * **63**: Voltage code (63 often represents **3.3 Volts**). * **BC**: Stability and Temperature code (e.g., **B** = ±50ppm, **C** = Industrial Temp Range). * **9O2**: Pulling Range/Control Voltage (indicates how much the frequency can be "tuned" via the control pin, e.g., ±100ppm). * **155.520**: The center frequency in **Megahertz (MHz)**. --- ### 4. Key Applications Because 155.520 MHz is a fundamental frequency for optical networking, this part is found in: 1. **SONET/SDH Systems:** OC-3 and STM-1 transmission rates. 2. **Phase-Locked Loops (PLLs):** Used to synchronize data streams. 3. **Fiber Channel:** High-speed storage networking. 4. **Base Stations:** Cellular infrastructure synchronization. ### 5. Circuit Integration Tips * **Decoupling:** Always place a 0.01µF to 0.1µF capacitor as close to the VDD pin as possible to filter noise. * **Termination:** Since this is likely an LVPECL output, ensure proper 50-ohm termination to Vcc-2V to prevent signal reflection. * **Control Voltage:** The "VC" (Voltage Control) pin should be driven by a low-noise DAC or filtered DC source to avoid introducing jitter. ---