Introduction to SFCA2512 Series Current Sensing Resistors

I. Product Overview

The SFCA2512 series current sensing resistors are high-precision electronic components made of metal-ceramic material. Featuring a short electrode, four-terminal design without side electrodes, and a standard size of 0.25×0.12 inches, these resistors exhibit excellent performance stability and reliability in current detection scenarios. They are widely applicable in various electronic equipment fields that have strict requirements for current measurement accuracy.

II. Product Model Interpretation

The product model of the SFCA2512 series consists of five parts, with the following meanings:

1. Series Number (SFCA2512): Represents short electrode, four-terminal, no side electrode design, with a size of 0.25×0.12 inches;
2. Material (M): Made of manganese-copper alloy (MnCu alloy), providing a foundation for stable resistor performance;
3. Power Rating: For example, W50 indicates 0.50 Watt, and 1W0 indicates 1.0 Watt, specifying the power-carrying capacity of the product;
4. Nominal Resistance Value: For example, 5mΩ corresponds to R005, and 10mΩ corresponds to R010, intuitively presenting the nominal resistance value;
5. Resistance Tolerance: D represents ±0.5%, and F represents ±1%, meeting the requirements of different precision scenarios.

III. Core Parameters and Performance

(I) Physical Specifications

The product dimensions strictly comply with standard specifications. Taking a typical model as an example, W (width) is 3.10±0.20mm, L (length) is 6.30±0.20mm, T (thickness) is 0.60±0.20mm, and other key dimensions such as A and D are within the specified tolerance range to ensure installation adaptability.

(II) Structure and Materials

1. Substrate: Alumina Ceramic substrate is adopted, which has excellent thermal conductivity and insulation performance;
2. Adhesion Layer: Epoxy resin is selected to ensure firm bonding between various structural layers;
3. Resistive Element: Made of copper alloy (Cu - alloy), ensuring the accuracy and stability of the resistance value;
4. Terminal Electrode: Composed of tin (Sn), nickel (Ni), and copper (Cu), improving welding performance and electrical conductivity;
5. Protective Coating: Green flame-retardant epoxy resin, meeting UL - 94 - V0 requirements, effectively protecting the internal structure;
6. Marking Coating: Black flame-retardant epoxy resin, also meeting UL - 94 - V0 requirements, clearly presenting product identification.

(III) Electrical Characteristics

The electrical parameters of different sub-series products have their own focuses, fully covering diverse application needs:

1. SFCA2512MW33 - series 0M50: Resistance 0.5mΩ, rated power 0.33 Watt, resistance tolerance ±0.5% (D)/±1% (F), Temperature Coefficient of Resistance (TCR) ±100ppm/℃;
2. SFCA2512MW50 - series R001~R002: Resistance 1~2mΩ, rated power 0.50 Watt, resistance tolerance ±0.5% (D)/±1% (F), standard TCR ±75ppm/℃, special TCR ±50ppm/℃;
3. SFCA2512M1W0 - series R003~R004: Resistance 3~4mΩ, rated power 1.0 Watt, resistance tolerance ±0.5% (D)/±1% (F), standard TCR ±50ppm/℃, special TCR ±30ppm/℃;
4. SFCA2512M1W0 - series R005~R100: Resistance 5~100mΩ, rated power 1.0 Watt, resistance tolerance ±0.5% (D)/±1% (F), standard TCR ±30ppm/℃, special TCR ±15ppm/℃.In addition, customized resistance products can be provided according to customer requirements.

(IV) Environmental and Reliability Performance

1. Operating Temperature Range: -55℃~155℃. Continuous full-load operation is allowed within 70℃; beyond 70℃, the load shall be adjusted according to the power derating curve;
2. Storage Conditions: Can be stored for 2 years in an airtight environment with temperature +10℃~40℃ and relative humidity ≤75%; can be stored for a maximum of 30 days without dew in an environment with temperature +10℃~60℃ and relative humidity 95%;
3. Reliability Tests: Passed a series of rigorous tests including Short Time Over Load, High Temp. Exposure, Low Temp. Storage, Moisture Load Life, Thermal Shock, Solderability, Resistance to Solder Heat, Mechanical Shock, and Substrate Bending. After all tests, the resistance value change meets the acceptance standard of ±(1.0%+0.5mΩ) or ±(2.0%+0.5mΩ), and the solder coverage area exceeds 95% in the solderability test, fully complying with the relevant requirements of IEC60115 - 1.

IV. Welding and Packaging Specifications

(I) Welding Requirements

1. Solder Pad Dimensions: P is 3.10mm, D is 2.00mm, W1 is 1.40mm, W2 is 0.70mm, suitable for specific pad layouts and stable current scenarios;
2. Welding Parameters: Reflow soldering shall follow the standard temperature curve; the temperature for soldering iron welding (hot air equipment) is 350℃, with a duration of 3~5 seconds; infrared, vapor phase, hot air and other welding heat sources are recommended to avoid product function damage caused by excessive temperature.

(II) Packaging Information

1. Packaging Quantity: 4000pcs per reel, with a weight of 270±50g;
2. Reel & Tape Specifications: The key dimension A±5mm is 178mm, N±2mm is 60mm, W1±1mm is 13mm, and other relevant dimensions comply with industry standards;
3. Seal Tape: Peeling Strength is 0.1 - 1.0N (10 - 100gf), ensuring packaging sealing performance and ease of use.

V. Lot Acceptance Test Requirements

Each batch of products (maximum batch quantity not exceeding 500Kpcs) must undergo strict incoming inspection, including the following test items:

1. Visual Inspection: Checked with a magnifying glass, no obvious stains, dirt, marking errors, damage, etc.;
2. Dimensions: Measured with calibrated gauges (such as calipers, microscopes, etc.) to ensure dimensions are within the specified range;
3. Resistance (Ro) of Individual Components: Measured by 4-wire resistance test technology at 25℃, and the resistance value meets the standard requirements;
4. Temperature Coefficient of Resistance (TCR): The resistance values at 25℃ and 125℃ are measured by the 4-wire method, substituted into the formula for calculation, and the result is within the specified range;
5. Insulation Resistance (Ri): Measured by a high ohm meter, and the insulation resistance between the protective coating and the resistive element is not less than 100MΩ.

VI. Conclusion

With its core advantages such as high precision, high reliability, and wide temperature adaptation range, combined with flexible customized services and a strict quality control system, the SFCA2512 series current sensing resistors can accurately match the current detection needs of various electronic equipment. From material selection to production inspection, every link follows strict standards to ensure the stable operation of the product under complex working conditions. Whether in industrial control, automotive electronics, consumer electronics or other fields, the SFCA2512 series is a trustworthy current sensing solution, providing a solid guarantee for the performance improvement and stable operation of electronic equipment.