The part number **I641-32BC9O2-155.520** refers to a high-precision **Voltage Controlled Crystal Oscillator (VCXO)** typically manufactured by ILSI America (now part of Abracon). These components are designed for high-speed networking and telecommunications applications. --- ### Technical Breakdown of the Part Number | Segment | Specification | Description | | :--- | :--- | :--- | | **I641** | Series Model | Represents a 5.0 x 7.0 mm Surface Mount (SMD) VCXO. | | **32** | Operating Voltage | Indicates a supply voltage of **3.3V DC**. | | **B** | Frequency Stability | Typically represents **±50 ppm** stability over temperature. | | **C** | Operating Temp | Industry standard for **0°C to +70°C** (Commercial grade). | | **9** | Pullability | Refers to the APR (Absolute Pull Range), usually **±100 ppm**. | | **O2** | Output Type | **LVPECL** (Low-Voltage Positive Emitter-Coupled Logic). | | **155.520** | Nominal Frequency | Operating frequency of **155.520 MHz**. | --- ### Key Electronic Characteristics #### 1. LVPECL Output The "O2" code signifies an **LVPECL** output. This is a differential signaling standard favored in high-frequency applications because: * It provides excellent noise immunity. * It supports very fast switching speeds (low jitter). * It requires specific termination (usually 50 ohms to $V_{cc} - 2V$). #### 2. Frequency (155.520 MHz) The frequency of **155.520 MHz** is a standard industry value used specifically for **SONET/SDH** (OC-3) optical networking rates. It is a fundamental building block for clock generation in fiber-optic communication. #### 3. VCXO Functionality As a **Voltage Controlled** oscillator, this device features a "Control Voltage" pin (Pin 1). By varying the voltage on this pin, the user can slightly "pull" or adjust the output frequency. This is essential for: * **Phase-Locked Loops (PLLs):** Synchronizing a local clock to an incoming data stream. * **Jitter Cleaning:** Smoothing out irregularities in a clock signal. --- ### Physical and Pin Configuration The I641 series typically uses a **6-pad ceramic package** measuring **7.0 x 5.0 mm**. | Pin Number | Function | | :--- | :--- | | 1 | Voltage Control ($V_c$) | | 2 | Enable/Disable (Tristate) | | 3 | Case Ground | | 4 | Output (Q) | | 5 | Complementary Output ($\bar{Q}$) | | 6 | Supply Voltage ($V_{dd}$) | --- ### Common Applications * **Telecommunications:** SONET / SDH / ATM. * **Networking:** Gigabit Ethernet and Fiber Channel. * **Data Recovery:** Clock and Data Recovery (CDR) circuits. * **Broadcasting:** Video synchronization equipment.