eFuse vs. PTC Fuse: Key Differences Explained

This article compares eFuse and PTC fuse, highlighting the key differences between them. These devices, along with one-shot fuses, are crucial for overcurrent protection in electronic circuits.

What is a PTC Fuse?

A PTC (Positive Temperature Coefficient) resettable fuse heats up when a short circuit occurs. This causes it to transition from a state of low resistance to a state of high resistance. Once the power is removed and the device cools down, it resets to its low resistance state.

One-shot fuses operate differently. They rely on the melting of a metal link when a high current event takes place.

PTC fuses come in two main types:

• Ceramic PTC: Primarily used in telecom applications where the resistance should not change after tripping.
• Polymer PTC: Commonly used in general electronic applications.

What is an eFuse?

An eFuse represents an IC protection solution that overcomes the limitations of discrete component-based circuit protection. It incorporates a FET (Field-Effect Transistor) to limit currents and/or voltages to safe levels during fault conditions.

The operating principle of an eFuse is distinct from that of one-shot or PTC fuses. Instead of relying solely on heat, an eFuse measures the current flowing in the circuit and shuts off an internal switch when the current exceeds a predefined limit.

Image Courtesy: Texas Instruments

For more information, refer to the advantages and disadvantages of eFuse.

Difference between eFuse and PTC Fuse

The following table outlines the key differences between eFuse and PTC fuse. The data is derived from “ON Semiconductor” test results based on the NIS5132MN2 eFuse and a similar polymer PTC device.