Current Sensing Precision Resistor

The Isabellenhütte CMK is a 1206 ISA-PLAN precision resistor designed for low-ohmic current sensing in compact power electronics and control circuits. The manufacturer positions it for applications including power hybrid systems, automotive control systems, parking brakes, frequency converters, switch mode power supplies and LED driver circuits.

Electrical performance depends on the selected resistance value. The 5 mΩ version is specified with <20 ppm/°C TCR from 20 °C to 60 °C, 4 W power rating at 70 °C, 1.5 W at 130 °C and internal heat resistance below 25 K/W, while the 8 mΩ version is rated at 3 W at 70 °C and <30 K/W. Values from 10 mΩ to 100 mΩ are specified with <50 ppm/K TCR, 1.25 W at 70 °C, 0.5 W at 130 °C and internal heat resistance below 80 K/W.

The series is AEC-Q200 qualified and supports reflow and IR soldering, with dielectric withstanding voltage of 200 V AC/DC and inductance below 3 nH. The datasheet also gives long-term and environmental test data including ±1.0 % operational life change after 2000 h at rated power and ±0.5 % after 1000 h at 85 °C/85 % RH under bias humidity conditions.

Key Features

• Product family: ISA-PLAN precision resistor, CMK series, 1206 package.
• Resistance values: 5 mΩ, 8 mΩ, and 10 mΩ to 100 mΩ.
• Tolerance options: ±1 % for 5 mΩ; ±1 % and ±5 % for 8 mΩ to 100 mΩ, depending on value availability.
• TCR (20 °C to 60 °C): <20 ppm/°C at 5 mΩ; <50 ppm/°C from 8 mΩ to 100 mΩ.
• Power rating at 70 °C: 4 W (5 mΩ), 3 W (8 mΩ), 1.25 W (10 mΩ to 100 mΩ).
• Power rating at 130 °C: 1.5 W (5 mΩ), 1 W (8 mΩ), 0.5 W (10 mΩ to 100 mΩ).
• Constant current capability: up to 28 A at 5 mΩ.
• Operating temperature range: −65 °C to +170 °C.
• Qualification: AEC-Q200 qualified.
• Mounting: reflow and IR soldering.
• Inductance: <3 nH.
• Dielectric withstanding voltage: 200 V AC/DC.