The **MHO321FCG-R** is a high-performance **Clock Oscillator** (Crystal Oscillator) manufactured by **NDK (Nihon Dempa Kogyo Co., Ltd.)**. It is designed for precision timing in electronic circuits, utilizing a CMOS output and a compact surface-mount (SMD) package. ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Component Type** | Crystal Oscillator (SPXO) | | **Output Type** | CMOS | | **Nominal Frequency Range** | 1 MHz to 125 MHz (Variable by specific sub-model) | | **Supply Voltage (Vcc)** | +1.8V, +2.5V, or +3.3V (Typical) | | **Frequency Stability** | ±20ppm to ±100ppm (Depending on grade) | | **Operating Temperature** | -40°C to +85°C (Industrial Grade) | | **Package Size** | 3.2 x 2.5 x 1.0 mm (3225 size) | | **Standby Function** | Included (Tri-state) | --- ### 2. Physical Construction and Pinout The device is housed in a 4-pad ceramic package. The internal circuitry consists of a high-quality quartz crystal blank paired with a low-power CMOS IC. #### Pin Configuration 1. **Pad 1: Standby (ST)** – High or Open enables output; Low puts the device in standby mode to save power. 2. **Pad 2: Ground (GND)** – Connected to the circuit common. 3. **Pad 3: Output** – The clock signal (Square wave). 4. **Pad 4: Vcc** – Power supply input. --- ### 3. Key Features * **Low Jitter:** Optimized for high-speed data transmission to minimize timing errors. * **Wide Temperature Range:** Suitable for harsh environments compared to standard consumer-grade oscillators. * **RoHS Compliant:** Lead-free and environmentally friendly construction. * **Compact Footprint:** The 3225 (3.2mm x 2.5mm) size is industry-standard for mobile and embedded applications. --- ### 4. Typical Applications The MHO321FCG-R is commonly used as a heartbeat or reference clock for: * **Microcontrollers (MCUs) & FPGAs:** Providing the system clock for logic operations. * **Networking Gear:** Routers, switches, and Ethernet controllers. * **Industrial Electronics:** Automation controllers and sensors requiring stable timing over a wide temperature range. * **Storage Devices:** SSD controllers and HDD interfaces. --- ### 5. Part Number Breakdown (General NDK Format) * **MHO:** Refers to the specific series/model line. * **321:** Indicates the physical dimensions (3.2 x 2.5 mm). * **FCG:** Internal codes for frequency stability, voltage, and output characteristics. * **R:** Usually denotes the packaging type (e.g., Tape and Reel).