The part number **MMU01020B3003JB300** refers to a high-precision, high-stability **MELF (Metal Electrode Leadless Face) resistor** manufactured by **Vishay Beyschlag**. Below is a detailed breakdown of its technical specifications and characteristics. --- ### 1. General Specifications | Feature | Specification | | :--- | :--- | | **Manufacturer** | Vishay Beyschlag | | **Series** | MMU 0102 (Micro MELF) | | **Resistance** | 300 kΩ (300,000 Ohms) | | **Tolerance** | ± 5% | | **Power Rating** | 0.3 W (at 70°C) | | **Temperature Coefficient** | ± 100 ppm/K | | **Package Type** | MELF 0102 (Cylindrical Surface Mount) | | **Operating Voltage** | 150 V (Maximum) | --- ### 2. Part Number Breakdown The alphanumeric code follows a specific logic used by Vishay: * **MMU 0102**: Indicates the series and physical size (Micro MELF). * **0B**: A code representing specific manufacturing process/plating. * **3003**: The resistance value. The first three digits are significant, and the last digit is the multiplier. * `300` + `10^3` = **300,000 Ω (300 kΩ)**. * **J**: Tolerance code. `J` stands for **± 5%**. * **B3**: Packaging code (typically refers to Bulk or Blister Tape). * **00**: Internal designator/Standard version. --- ### 3. Physical Attributes (MELF vs. Flat Chip) Unlike standard rectangular SMD resistors (thick film), this is a **MELF** resistor. * **Cylindrical Design:** Provides superior thermal dissipation and pulse load capability. * **Thin Film Technology:** The resistive layer is deposited on a high-grade ceramic body, offering better stability and lower noise than thick film counterparts. * **Dimensions:** Roughly 2.2 mm in length and 1.1 mm in diameter. --- ### 4. Key Advantages and Applications #### Advantages * **High Reliability:** Excellent stability under harsh environmental conditions (moisture, temperature cycling). * **Pulse Handling:** Because of the cylindrical shape and thin film construction, it handles energy pulses better than standard 0805 or 0603 flat resistors. * **Low Noise:** Ideal for precision analog circuits. #### Typical Applications 1. **Industrial Electronics:** Control systems and sensors. 2. **Automotive:** Lighting, engine control units, and braking systems (AEC-Q200 qualified versions available). 3. **Telecommunications:** Base stations and infrastructure. 4. **Medical Equipment:** High-precision diagnostic tools. ---