The part number **I640-31FC3O2-155.520** refers to a high-precision **Voltage Controlled Crystal Oscillator (VCXO)**, typically manufactured by companies like ILSI (now part of Abracon) or similar frequency control specialists. Below is a detailed breakdown of its electronic specifications and characteristics based on the standard naming conventions for this series. --- ### 1. Part Number Decoder | Segment | Meaning | Specification | | :--- | :--- | :--- | | **I640** | Series/Model | 5x7mm Surface Mount VCXO | | **3** | Supply Voltage | 3.3V DC | | **1** | Frequency Stability | ±50 ppm (Commonly) | | **FC** | Operating Temp | -40°C to +85°C (Industrial Grade) | | **3** | Duty Cycle | 45% / 55% | | **O2** | Output Type | CMOS / HCMOS | | **155.520** | Frequency | 155.520 MHz | --- ### 2. Technical Specifications #### Frequency and Performance * **Center Frequency:** 155.520 MHz. This specific frequency is a standard telecommunications rate, often used in **SONET/SDH** (OC-3) networking equipment. * **Frequency Pulling Range:** As a VCXO, the output frequency can be adjusted (pulled) by varying the control voltage on Pin 1. Typically, the range is ±50ppm to ±100ppm. #### Electrical Characteristics * **Supply Voltage ($V_{dd}$):** 3.3V ±5%. * **Output Logic:** HCMOS. This provides a rail-to-rail square wave signal suitable for driving clock buffers or FPGAs. * **Current Consumption:** Generally ranges from 25mA to 45mA depending on the specific internal crystal design. #### Mechanical & Environmental * **Package Size:** 5.0mm x 7.0mm (6-pad SMD package). * **Operating Temperature:** -40°C to +85°C, making it suitable for outdoor networking hardware and industrial applications. --- ### 3. Common Applications Due to the specific 155.520 MHz frequency, this component is predominantly found in: 1. **Optical Networking:** Timing for Synchronous Optical Networking (SONET). 2. **Phase-Locked Loops (PLLs):** Used as a local oscillator that can be synchronized to a reference clock. 3. **Data Communications:** Gigabit Ethernet and Fiber Channel synchronization. 4. **Base Stations:** Timing synchronization in cellular infrastructure. --- ### 4. Pin Configuration (Standard 6-Pad) | Pin | Function | Description | | :--- | :--- | :--- | | **1** | Vc | Voltage Control (Adjusts frequency) | | **2** | E/D or NC | Enable/Disable (Tri-state) or No Connect | | **3** | GND | Ground | | **4** | Output | Frequency Output Signal | | **5** | NC | No Connection | | **6** | Vdd | Supply Voltage (+3.3V) |