Fast-acting Electronic Fuse For High-Power Applications


New 8-48V 4A programmable electronic fuse adds value-added features for robust system control

Fuses are one of the essential components that you can use to protect electrical components from overcurrent. ST develops E-fuses (electronic fuses) that can replace the standard mechanical fuses generally present on DC power rails, allowing a more precise, reliable and cost-effective protection.

ST’s STEF01 is a new integrated electronic fuse optimized for monitoring output current and the input voltage on DC power lines. ST has designed the device to extend the benefits of fast-acting overload protection to applications at higher power ratings.


The company is asserting that the device can sustain up to 4A continuous current over a wide operating input voltage range of 8V to 48V, with low insertion loss thanks to its integrated low-RDS(ON) VIPower MOSFET.

According to ST, the STEF01 is able to detect and react to overcurrent and overvoltage conditions when connected in series to the main power rail. When an overload condition occurs, the device limits the output current to a user-defined safe value. If the anomalous overload condition persists, the device goes into an open state, disconnecting the load from the power supply.

Value-added features include dV/dt control to prevent excessive inrush current during startup or hot-swap insertion.

Programmable Under-Voltage Lockout (UVLO), also set using external components, allows the user to fine-tune the desired voltage-rail minimum value to suit the load requirements.

Further features include thermal shutdown with latching or auto-retry, and maximum dissipated-power protection, which each prevent exceptionally high power from damaging the STEF01 when starting up into heavy capacitive loads, or during large load transients or short-circuits at high voltage.

High-Power Electronic Fuse with Value-Added Features for Safety and Reliability

Also provided is a power-good indicator, and an enable/fault pin that can be used as either a status monitor or to control the device.

A dedicated gate-driver output for controlling an external N-channel MOSFET simplifies implementation of reverse-current protection.

Main Applications:

  • Hot board insertion
  • Electronic circuit breaker/power busing
  • Industrial/alarm/lighting systems
  • Distributed power systems
  • Telecom power modules

The STEF01 is available now in 14-pin HTSSOP14 package, priced from $1.00 for orders of 1000 pieces. For further information, click here.



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