The MF72 series 12D-11 is a directly heated, power-type negative temperature coefficient thermistor designed to suppress startup inrush current in electronic devices.
It has a rated zero-power resistance of 12Ω ±20%, tested at 1.5VDC at 25°C, and a material constant B value of 2800K ±10%. During startup, it exhibits a high-resistance state to limit surges. During operation, the resistance drops to a residual value of 0.46Ω due to self-heating, achieving steady-state 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 of 2A supports capacitive loads of 220μF in 240V systems or 820μF 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 suitable for surge protection in switching power supplies, UPSs, electronic ballasts, energy-saving lamps, and displays. The device utilizes a phenolic resin package with CP wire leads and offers four mounting configurations: inward-curved, outward-curved, side-curved, and straight-leg.