### PL680-39OCL-R Technical Analysis The **PL680-39OCL-R** is a high-performance **Low Phase Noise Clock Multiplier IC** developed by Microchip Technology (formerly PhaseLink). It is specifically designed for high-frequency clock generation in networking and telecommunications equipment. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Type** | Clock Multiplier / Buffer | | **Output Type** | LVPECL (Low-Voltage Positive Emitter-Coupled Logic) | | **Input Frequency** | 19 MHz to 40 MHz (Fundamental Crystal or Reference) | | **Output Frequency** | Up to 640 MHz (depending on multiplication factor) | | **Supply Voltage** | 2.5V or 3.3V | | **Package** | TSSOP-16 | | **Operating Temp** | 0°C to +70°C (Commercial Grade) | | **Jitter Performance** | < 1ps RMS (Integrated from 12kHz to 20MHz) | --- ### 2. Functional Components * **Phase-Locked Loop (PLL):** The core of the device, which locks onto the input reference frequency and multiplies it to a higher target frequency while maintaining low jitter. * **LVPECL Output Driver:** Provides high-speed, differential signals suitable for long-distance PCB traces and high-frequency clocking. * **Voltage Controlled Oscillator (VCO):** Internal high-speed oscillator tuned to minimize phase noise. * **Output Enable (OE):** A control pin that allows the outputs to be disabled (high-impedance state) for power saving or testing. --- ### 3. Part Number Breakdown Understanding the suffix is critical for procurement and design: * **PL680-39:** The base part family (Low Jitter Multiplier). * **O:** Package type (TSSOP - Thin Shrink Small Outline Package). * **C:** Commercial temperature range ($0^{\circ}C$ to $70^{\circ}C$). * **L:** Lead-free / RoHS compliant. * **-R:** Tape and Reel packaging (standard for automated SMT assembly). --- ### 4. Typical Applications 1. **Fiber Channel & Ethernet:** Generating 156.25 MHz or 312.5 MHz clocks for 10GbE systems. 2. **SONET/SDH:** High-precision timing for optical networks. 3. **Storage Area Networks (SAN):** Low-latency clocking for data centers. 4. **CPU/FPGA Clocking:** Providing high-speed differential reference clocks to FPGAs or high-end processors. --- ### 5. Implementation Considerations * **Termination:** As an LVPECL device, it requires specific termination resistors (typically 50 ohms to $V_{CC} - 2V$) to ensure signal integrity. * **Decoupling:** High-speed PLLs are sensitive to power supply noise. It is recommended to use 0.1µF and 0.01µF bypass capacitors as close to the $V_{DD}$ pins as possible.