The **CRO2137A-LF** is a high-performance **Voltage Controlled Oscillator (VCO)** manufactured by Skyworks Solutions (formerly Z-Communications). It is primarily designed for high-frequency signal generation in telecommunications and radio frequency (RF) applications. --- ### 1. Technical Specifications The following table outlines the core electrical characteristics of the CRO2137A-LF: | Parameter | Specification | Unit | | :--- | :--- | :--- | | **Frequency Range** | 2137 – 2137 | MHz | | **Tuning Voltage** | 0.5 – 4.5 | Vdc | | **Output Power** | 0 ± 3 | dBm | | **Phase Noise (@10kHz offset)** | -110 (typ) | dBc/Hz | | **Harmonic Suppression (2nd)** | -15 (typ) | dBc | | **Supply Voltage (Vcc)** | 5 | Vdc | | **Supply Current (Icc)** | 25 (max) | mA | | **Operating Temperature** | -40 to +85 | °C | --- ### 2. Key Electronic Components & Features * **Coaxial Resonator (CRO):** The "CRO" prefix indicates that this oscillator utilizes a ceramic coaxial resonator. This technology provides superior **Phase Noise** performance compared to standard LC-based oscillators, making it ideal for narrow-band applications. * **Varactor Diode Tuning:** It uses internal varactor diodes to shift the frequency. By applying a control voltage ($V_{tune}$), the capacitance of the diode changes, altering the resonant frequency of the circuit. * **Buffer Amplifier:** The internal circuit usually includes a buffer stage to isolate the oscillator from load variations (load pulling), ensuring frequency stability even if the output impedance changes. * **LF (Lead-Free):** The "LF" suffix denotes that the component is RoHS compliant, meaning it is manufactured without hazardous substances like lead. --- ### 3. Application Areas The CRO2137A-LF is commonly integrated into the following systems: 1. **Phase-Locked Loops (PLLs):** Acts as the frequency-generating element within a larger feedback loop. 2. **Base Stations:** Used in cellular infrastructure (e.g., UMTS/LTE bands) for signal modulation and demodulation. 3. **Satellite Communications:** High-stability local oscillator for frequency conversion. 4. **Test Equipment:** RF signal generators where low phase noise is critical for measurement accuracy. --- ### 4. Typical Connection Diagram (Pinout) | Pin Number | Function | Description | | :--- | :--- | :--- | | **1** | Vt | Control voltage input to tune frequency | | **2** | Vcc | DC Power supply (+5V) | | **3** | RF Out | High-frequency signal output | | **Case** | GND | Common ground connection |