The MF72 series 20D-15 is a directly heated, power-type negative temperature coefficient thermistor designed for high-precision inrush current suppression in electronic devices. Its rated zero-power resistance is 20Ω ± 20%, verified by 1.5VDC testing at 25°C. A material constant B value of 2950K ± 10% ensures stable temperature response. A thermal time constant of approximately 86 seconds, combined with a dissipation factor of approximately 18mW/°C, and a heat capacity of 1548mJ/°C provide strong surge protection. It offers a maximum steady-state current of 4A and a low residual resistance of 0.288Ω. It supports capacitive loads of 220μF for 240V systems or 820μF for 120V systems. The device features a standardized 17.5mm diameter and 6mm thickness, with four lead configurations: inward-curved, outward-curved, side-curved, and straight. The phenolic resin package and CP wire leads ensure mechanical durability, and the device operates in harsh environments from -40°C to +200°C.
Typically used in high-power switching power supplies, industrial-grade UPS systems, and motor drive equipment, it optimizes startup safety in large-capacity capacitor circuits through precise thermal response characteristics.