The **PLL520-19SC-R** is a specialized high-performance Clock Multiplier IC designed for low-power and low-phase noise applications. It is part of a family of Phase-Locked Loop (PLL) components typically used in networking and storage systems. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Manufacturer** | PhaseLink (now part of Microchip/Micrel) | | **Function** | VCXO (Voltage Controlled Crystal Oscillator) / Clock Multiplier | | **Input Frequency** | 10MHz to 27MHz (Crystal or Reference) | | **Output Frequency** | Up to 135MHz (depending on internal settings) | | **Operating Voltage** | 3.3V (±10%) | | **Package Type** | SOP-8 (Small Outline Package, 8-pin) | | **Output Logic** | CMOS / TTL | --- ### 2. Functional Description The device integrates several electronic sub-systems into a single 8-pin package: * **Phase-Locked Loop (PLL):** The core of the chip. It synchronizes the output frequency with the input reference to ensure high stability. * **Voltage Controlled Oscillator (VCO):** Generates the high-frequency signal. * **Internal Loop Filter:** Reduces the need for external capacitors/resistors, saving PCB space. * **VCXO Capability:** It can be used as a Voltage Controlled Crystal Oscillator, allowing the output frequency to be "pulled" or fine-tuned via an analog control voltage. --- ### 3. Pin Configuration (SOP-8) Below is the typical pinout logic for the 520-19 series: | Pin # | Name | Description | | :--- | :--- | :--- | | 1 | **VIN** | Voltage Control input for VCXO | | 2 | **XIN / REF** | Crystal connection or Reference Clock input | | 3 | **GND** | Ground connection | | 4 | **XOUT** | Crystal connection (Leave open if using REF) | | 5 | **CLKOUT** | Clock Output | | 6 | **VDD** | Power Supply (3.3V) | | 7 | **S0 / OE** | Selection bit or Output Enable (Model dependent) | | 8 | **S1** | Selection bit for frequency multipliers | --- ### 4. Common Applications * **Set-Top Boxes:** For synchronizing audio/video clocks. * **Data Networking:** Providing stable reference clocks for Gigabit Ethernet. * **Storage (SAN/NAS):** Used in Fibre Channel applications. * **Clock Jitter Attenuation:** Cleaning up "noisy" input clocks to provide a steady output. --- ### 5. Part Number Breakdown * **PLL520-19:** The specific series/architecture family. * **SC:** Standard Commercial temperature range (0°C to +70°C). * **R:** Denotes "Tape and Reel" packaging for automated assembly. ---