STMicroelectronics 5 V and 12 V power line protection based on STEF05 and STEF12 electronic fuses STEVAL-IFP021V1 STEVAL-IFP021V1 Data Sheet

   

   

   

For further information contact your local STMicroelectronics sales office.

January 2012

Doc ID 022688 Rev 1

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5 V and 12 V power line protection based on STEF05

and STEF12 electronic fuses

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Input voltages: 5 V and 12 V 

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Continuous current: 3.6 A (typ.) each 

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Adjustable slew rate for output voltage

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Overvoltage clamp

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Undervoltage lockout

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Programmable short-circuit current limit

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Overload current limit

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Controlled output voltage ramp

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Thermal latch protection

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Fault condition flag

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Enable pin

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RoHS compliant

The STEVAL-IFP021V1 demonstration board is 
based on the STEF05 and STEF12 electronic 
fuses (E-Fuses).

It is designed to help users evaluate the benefit of 
the complete protection offered by the E-Fuse 
family and to customize their own application. 

The E-Fuse family of hot-swap converters is 
designed to replace the mechanical fuses on low 
voltage power lines.

The STEF05 and STEF12 are integrated 
electronic fuses optimized for monitoring output 
current and input voltage. 

Connected in series to the 5 V/12 V rails, they are 
capable of protecting the electronic circuitry on 
the output from overcurrent and overvoltage.

The turn-on time is programmable by means of an 
external capacitor, allowing control of the inrush 
current at startup and during hot-swaps.

When an overload condition occurs, the E-Fuse 
limits the output current to a predefined safe 
value. If the anomalous overload condition 

persists, it goes into an open state, disconnecting 
the load from the power supply. 

If a continuous short-circuit is present on the 
board, when power is re-applied the E-Fuse 
initially limits the output current to a safe value, 
and then again goes into an open state. 

Both devices are equipped with a thermal 
protection circuit.

The intervention of the thermal protection is 
signaled to the board monitoring circuits through 
a signal on the enable/fault pin that can be 
connected to other parts belonging to the same 
family to cause a simultaneous shutdown during 
failure events. 

Unlike mechanical fuses, which must be 
physically replaced after a single event, E-Fuses 
do not degrade in their performance after short-
circuit/thermal protection interventions and can be 
reset either by re-cycling the supply voltage or by 
using the enable pin.