The MF72 series 20D-11 is a directly heated, power-type negative temperature coefficient thermistor designed to precisely suppress startup inrush current in electronic devices.
Its rated zero-power resistance is 20Ω ± 20%, tested at 1.5VDC at 25°C, and its material constant B value is 2950K ± 10%. It provides a high-resistance state during startup, effectively limiting surges. During steady-state operation, the resistance self-heats to a residual value of 0.51Ω, ensuring 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 excellent surge resistance. Its maximum steady-state current is 2A, compatible with 100μF capacitive loads 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's designed specifically for surge protection of low- and medium-power devices such as switching power supplies, UPS systems, and electronic ballasts. Encapsulated in phenolic resin and with CP wire leads, the device offers four lead configurations: inward curvature, outward curvature, side curvature, and straight, meeting the thermal stability requirements of various installation scenarios.