The **LTCEC-12503-R/Q** refers to a high-precision, automotive-grade current sense resistor series, typically manufactured by specialists like **LTA (Lian-Sheng)** or similar precision component vendors. This specific part number follows a modular naming convention used to define its electrical and physical characteristics. --- ### 1. Part Number Breakdown Based on standard industry nomenclature for this series: | Segment | Meaning | Specification Details | | :--- | :--- | :--- | | **LTCEC** | **Series Code** | Low TCR, Metal Foil / Metal Plate Current Sense Resistor. | | **1250** | **Case Size** | Metric 1250 (Inches: **5025**). Dimensions are approx. 5.0mm x 2.5mm. | | **3** | **Power Rating** | Indicates **3 Watts** (High power density for this footprint). | | **-R** | **Resistance Value** | Signifies a decimal point for milliohms (e.g., R001 = 1mΩ). | | **-Q** | **Qualification** | Usually denotes **AEC-Q200** (Automotive Grade) compliance. | --- ### 2. Key Electrical Characteristics These resistors are designed for "Shunt" applications where measuring high current with minimal heat loss is critical. * **Resistance Range:** Typically ranges from **0.5mΩ to 500mΩ**. * **Temperature Coefficient (TCR):** Very low (usually **±50ppm/°C** or better), ensuring the resistance doesn't drift as the component heats up. * **Tolerance:** High precision, often available in **±0.5% or ±1%**. * **Construction:** Metal alloy plate technology. This provides superior heat dissipation compared to standard thick-film resistors. --- ### 3. Physical Attributes (1250 / 5025 Metric) The 1250 size is specifically chosen for high-current applications because the larger surface area (compared to a 1206) allows for better thermal management. | Feature | Description | | :--- | :--- | | **Mounting Type** | Surface Mount (SMD/SMT) | | **Terminal Material** | Usually Tin (Sn) over Nickel (Ni) barrier. | | **Operating Temp** | -55°C to +170°C (Extended range due to Metal Foil). | --- ### 4. Typical Applications Because of the **-Q (AEC-Q200)** rating, these are most commonly found in: 1. **Automotive Systems:** Battery Management Systems (BMS), Electronic Power Steering (EPS), and Motor Controllers. 2. **Industrial Power:** DC-DC converters and high-efficiency power supplies. 3. **Consumer Electronics:** Laptop battery charging circuits and power tools. --- ### 5. Summary Table | Parameter | Specification | | :--- | :--- | | **Type** | Metal Plate Current Sense | | **Power** | 3.0W | | **Package** | 5025 (2010 equivalent or metric 1250) | | **Grade** | Automotive AEC-Q200 | | **Inductance** | Low (< 5nH) |