The **PLL602-38NSCL-R** is a high-performance, low-power Clock Generator Integrated Circuit (IC) developed by Microchip (formerly PhaseLink). It is specifically designed to work with 25MHz crystals to generate high-frequency, low-jitter outputs suitable for networking and PCIe applications. ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Part Number** | PLL602-38NSCL-R | | **Type** | Clock Generator / Frequency Multiplier | | **Input Frequency** | 25 MHz (Crystal or Reference Clock) | | **Output Frequency** | 100 MHz (typically for PCIe) | | **Output Type** | HCSL (Host Clock Signal Level) | | **Operating Voltage** | 2.5V to 3.3V | | **Package Type** | SOP-8 (Small Outline Package) | | **Operating Temp** | 0°C to +70°C (Commercial) | --- ### 2. Functional Components The IC operates using several internal stages to convert a low-frequency crystal input into a high-stability differential output: 1. **Crystal Oscillator (XO) Input:** Accepts a 25MHz fundamental mode crystal. It includes internal load capacitance to simplify PCB design. 2. **Phase-Locked Loop (PLL):** The "brain" of the chip. It multiplies the 25MHz input by a factor of 4 to achieve a 100MHz output. 3. **HCSL Output Driver:** Converts the internal CMOS signal into a differential HCSL signal. HCSL is the standard signaling for PCI Express (PCIe) due to its high speed and low power consumption. 4. **Output Enable (OE):** Allows the system to turn the clock output on or off for power saving or synchronization. --- ### 3. Pin Configuration (SOP-8) | Pin # | Name | Description | | :--- | :--- | :--- | | 1 | XIN | Crystal Input or Reference Clock | | 2 | XOUT | Crystal Output (Leave floating if using Ref Clock) | | 3 | VDD | Power Supply (2.5V or 3.3V) | | 4 | GND | Ground | | 5 | CLK+ | Non-inverting HCSL Output | | 6 | CLK- | Inverting HCSL Output | | 7 | OE | Output Enable (Active High) | | 8 | NC | No Connection | --- ### 4. Application Use Cases * **PCI Express (Gen 1, 2, and 3):** Providing the 100MHz reference clock required for data lanes. * **Network Switches/Routers:** Synchronizing high-speed data transfers. * **Storage Area Networks (SAN):** Used in Fibre Channel or SATA controllers. * **Embedded Systems:** Where low-jitter and small form factors are required. --- ### 5. Part Number Suffix Breakdown * **NSCL:** Indicates the package type (SOP-8) and specific output configuration (HCSL). * **-R:** Indicates "Tape and Reel" packaging, used for automated SMT (Surface Mount Technology) assembly.