This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to

change without notice.

March 2013

DocID024394 Rev 1

1/19

19

STEF05D

Electronic fuse for 5 V line

Datasheet

Features

 Continuous current typ: 3.6 A

 N-channel on-resistance typ: 40 m

 Enable/fault functions

 Output clamp voltage typ: 6.65 V

 Undervoltage lockout

 Short-circuit limit

 Overload current limit

 Controlled output voltage ramp

 Thermal latch typ: 165 °C

 Uses tiny capacitors

 Operating junction temp. - 40 °C to 125 °C

 Available in DFN10 (3 x 3 mm).

Applications

 Hard disk drives

 Solid state drives (SSD)

 Hard disk and SSD arrays

 Set-top boxes

 DVD and Blu-ray disc drivers

Description

The STEF05D is an integrated electronic fuse

optimized for monitoring output current and input

voltage. Connected in series to a 5 V rail, it is

capable of protecting the electronic circuitry on its

output from overcurrent and overvoltage. The

device has a controlled delay and turn-on time.

When an overload condition occurs, the

STEF05D 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.

The device is equipped with a thermal protection

circuit. The intervention of the thermal protection

is signal led to the board monitoring circuits

through a signal on the Fault pin.

Unlike mechanical fuses, which must be

physically replaced after a single event, the E-

fuse does not degrade in its performance after

short-circuit/thermal protection interventions and

it is reset either by recycling the supply voltage or

using the Enable pin.

The companion chip for 12 V power rails is also

available with part number STEF12.

DFN10 (3 x 3 mm)

Table 1.

Device summary

Order code

Package

Packaging

STEF05DPUR

DFN10 (3 x 3 mm)

Tape and reel

www.st.com