The **CS-300-DFC-R4D2T4** is a high-precision, high-frequency Oven Controlled Crystal Oscillator (OCXO) manufactured by Microchip (formerly Vectron International). It is specifically designed for telecommunications and timing synchronization applications. --- ### 1. Technical Specifications Table | Feature | Specification | | :--- | :--- | | **Part Series** | CS-300 | | **Output Frequency** | Custom (typically in the 10 MHz to 100 MHz range) | | **Package Type** | Surface Mount Device (SMD) | | **Supply Voltage** | +3.3 VDC or +5.0 VDC (Variant dependent) | | **Output Type** | CMOS or Sinewave | | **Stability** | ±10 ppb to ±100 ppb (Temperature dependent) | | **Operating Temp** | -40°C to +85°C (Standard Industrial) | --- ### 2. Breakdown of the Part Number Logic The alphanumeric suffix defines the specific electronic characteristics of the component: * **CS-300**: The base series for high-stability OCXOs. * **DFC**: Refers to the physical package configuration and pinning (Dual-inline or specific SMD footprint). * **R4**: Usually denotes the **Temperature Stability** rating (e.g., ±50 ppb over the operating range). * **D2**: Specifies the **Supply Voltage** (often 3.3V) and the **Output Waveform** (typically CMOS). * **T4**: Represents the **Operating Temperature Range** (T4 often signifies -40°C to +85°C). --- ### 3. Key Electronic Subsystems This device is an "Oven Controlled" oscillator, meaning it contains several integrated circuits and passive components to maintain a constant internal temperature: #### A. The Crystal Resonator The heart of the part is an **SC-cut (Stress Compensated)** quartz crystal. SC-cut crystals are used because they are less sensitive to thermal shock and mechanical stress compared to standard AT-cut crystals. #### B. The Heating Circuit (The "Oven") To prevent frequency drift caused by ambient temperature changes, the internal crystal is wrapped in a heating element. A thermistor senses the temperature, and a control loop maintains the crystal at its "turnover point" (the temperature where the frequency-vs-temp curve is flattest). #### C. Voltage Regulation & Buffer The electronic assembly includes: * **Internal LDO:** To ensure power supply noise does not translate into phase noise. * **Output Buffer:** To provide a clean, high-speed CMOS or Sinewave signal capable of driving external loads without affecting the oscillator's stability. --- ### 4. Common Applications * **Base Stations (LTE/5G):** Providing the master clock for cellular towers. * **Synchronous Ethernet:** Maintaining timing across high-speed data networks. * **Test & Measurement:** Acting as a reference clock for frequency counters and synthesizers.