RXEF090 – RAYCHEM

The RXEF090 from RAYCHEM (now TE Connectivity) is a radial-leaded, polymeric positive temperature coefficient (PPTC) resettable fuse designed for overcurrent protection in low-voltage DC circuits. This device exhibits a hold current (Ihold) of 900mA (0.9A) and is rated for a maximum voltage (Vmax) of 72VDC. The RXEF090’s trip current (Itrip), the current at which the device switches to a high-resistance state, is higher than the hold current, providing a margin for normal operating current fluctuations. After the overcurrent condition is removed and power is cycled, the device resets to a low-resistance state, allowing circuit operation to resume. The radial lead configuration facilitates through-hole mounting on printed circuit boards. The device’s resistance increases sharply with temperature when the trip current is exceeded, limiting the fault current and protecting downstream components. It is commonly used in applications such as USB port protection, battery charging circuits, and general electronic equipment.