The MF72 series 22D-11 is a directly heated, power-type negative temperature coefficient thermistor designed to suppress inrush current during startup of electronic devices.
It has a rated zero-power resistance of 22Ω ± 20%, tested at 1.5VDC at 25°C, and a material constant B value of 2950K ± 10%. It exhibits a high-resistance state during startup, providing enhanced inrush current limiting. During steady-state operation, the resistance self-heats to a residual value of 0.56Ω, maintaining high efficiency and low power consumption.
The product of a 50-second thermal time constant and a 14mW/°C dissipation factor reaches 700mJ/°C, providing a robust surge protection. Its maximum steady-state current of 2A accommodates capacitive loads of 100μF in 240V systems or 390μF in 120V systems. Its compact design features a diameter of 12mm, a thickness of 5.5mm, and lead spacing of 7.5mm and 5mm.
With an operating temperature range of -40°C to +175°C, it is designed for circuits with low capacitive loads and is suitable for applications such as power converters, electronic energy-saving lamps, and heaters. The device utilizes a phenolic resin package with CP wire leads and is available in four package configurations: inward curvature, outward curvature, side curvature, and straight lead, ensuring superior thermal management in high-temperature environments.