XF065 Resettable Fuse PTC 72V @ 0.65A - (AD55231)

Description:

This is a handy little device that can prevent your system from smoking. A resettable fuse (also known as a PTC) is a resistor with unique properties.

For this model, if your circuit attempts to draw more than 650mA of current (if you have a bad short circuit, for example), the PTC will "trip" (heat up). The increased resistance (tripping state) would break the circuit and allow only a small amount of current to leak through.

The leakage current may still be enough to damage some electronic components, but it's much lower than the 3A the short may have allowed. By removing the short, the PTC "resets" and allows current of up to 650mA to flow again. It's a resettable fuse that protects your system! Good for use in battery-powered devices that need protection against accidental high-current discharges.

The thermal images below clearly show what happens when the PTC trips. The first thermal image shows a voltage regulator circuit in its normal state. In the second image, the circuit is shorted. Note how hot the PTC is (213°F!) as it limits the amount of damaging current passing through the circuit.

Data sheet