The MF72 series 22D-7 directly heated power negative temperature coefficient thermistor is specifically designed for inrush current suppression in electronic equipment. This device provides a high 22Ω resistance at the moment circuit power is applied, effectively limiting capacitor charging current. Through self-heating, its resistance rapidly decays to a residual resistance of 1.11Ω, maintaining steady-state low power consumption. Its 2800K material constant ensures stable and consistent resistance-temperature characteristics.
The device has a rated zero-power resistance of 22Ω ±20%, calibrated at 1.5VDC at 25°C. A 30-second thermal time constant and a 9mW/°C dissipation factor combine to produce a 270mJ/°C heat capacity, providing strong surge protection. Its maximum steady-state current of 0.6A supports capacitive loads of 68μF in 240V systems or 270μF in 120V systems.
It operates over a wide temperature range of -40°C to 150°C and has passed 200°C extreme temperature cycling and 1000 cycles of 0.6A electrical stress shock testing. This device is suitable for switching power supplies, electronic ballasts, and lighting control systems. Its fast response and low residual resistance optimize system efficiency and extend the service life of critical components.
Its compact 9mm diameter wafer, integrated with a 5mm thickness, features a phenolic resin encapsulation and CP leads. It is available in standard inward-curved, outward-curved, side-curved, and straight-leg mounting options.