DocID024394 Rev 1

9/19

STEF05D

Typical application

5.1.2

Normal operating condition

The STEF05D E-fuse behaves like a mechanical fuse, buffering the circuitry on its output

with the same voltage shown at its input, with a small voltage fall due to the N-channel

5.1.3

Output voltage clamp

This internal protection circuit clamps the output voltage to a maximum safe value, typically

6.65V, if the input voltage exceeds this threshold.

5.1.4

Current limiting

When an overload event occurs, the current limiting circuit reduces the conductivity of the

power MOSFET, in order to clamp the output current at the value selected externally by

5.1.5

Thermal shutdown

If the device temperature exceeds the thermal latch threshold, typically 165°C, the thermal

shutdown circuitry turns the power MOSFET off, thus disconnecting the load. The EN/Fault

pin of the device will automatically be set at an intermediate voltage, in order to signal the

overtemperature event.

From this condition the E-fuse can be reset either by cycling the supply voltage or by pulling

5.2

As shown in Figure 3, the device uses an internal N-channel sense FET with a fixed ratio, to

monitor the output current and limit it at the level set by the user.

following theoretical formula, together with the graph in Figure 13:

Equation 1

5.3

output voltage ramp time.

Given the desired time interval

t during which the output voltage goes from zero to his

following theoretical formula:

42

Ishort

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