The **PL580-37OCL-R** is a high-performance, low-phase-noise **VCXO (Voltage Controlled Crystal Oscillator)** IC produced by Microchip (formerly PhaseLink). It is specifically designed for high-frequency synthesis in fiber-optic communications and networking hardware. --- ### ## Technical Specifications Below are the primary electrical characteristics of the PL580-37OCL-R: | Feature | Specification | | :--- | :--- | | **Output Type** | LVPECL (Low-Voltage Positive Emitter-Coupled Logic) | | **Frequency Range** | 640MHz to 800MHz (based on 3rd overtone crystals) | | **Supply Voltage (VDD)** | 2.5V or 3.3V | | **Phase Jitter** | < 0.3ps RMS (12kHz to 20MHz) | | **Pull Range** | ±100 ppm (typical) | | **Package Type** | 16-pin TSSOP or SOP | | **Operating Temp** | 0°C to +70°C (Commercial Grade) | --- ### ### Key Electronic Components & Internal Logic 1. **Oscillator Core:** Unlike standard oscillators, this IC uses a specialized circuit designed to work with high-frequency **3rd Overtone Crystals**. This allows for much higher stability at high frequencies compared to fundamental mode crystals. 2. **LVPECL Output Stage:** The device uses **Differential LVPECL** outputs. This is critical for high-speed electronics because differential signaling rejects common-mode noise and provides sharp timing edges required for GigE and SONET applications. 3. **Voltage Control (VC) Pin:** The "Voltage Controlled" aspect means that by applying a DC voltage (typically 0V to VDD) to the tuning pin, the user can slightly "pull" or adjust the output frequency. This is essential for **Phase-Locked Loops (PLLs)** to synchronize clocks. 4. **Varactor Diode Integration:** Internally, the chip includes integrated varactors that change capacitance based on the control voltage, eliminating the need for external tuning components. --- ### ### Typical Application Circuit When designing a PCB for this part, the following connections are standard: ```mermaid graph LR A[V-Control Input] --> B(PL580-37) C[High-Freq Crystal] --- B B --> D[OUT Positive] B --> E[OUT Negative] F[3.3V VDD] --> B ``` --- ### ### Usage Recommendations * **Termination:** LVPECL outputs require specific termination (usually 50 ohms to $V_{DD} - 2V$) to function correctly and prevent signal reflections. * **Decoupling:** Use a 0.1µF ceramic capacitor as close to the VDD pin as possible to minimize power supply noise, which directly impacts phase jitter. * **PCB Layout:** Since this operates in the 600-800MHz range, the output traces must be impedance-controlled (usually 100-ohm differential).