Circuit Protection Misc Electronic Fuse for 3.3V Line

The STEF033 is an integrated electronic fuse optimized for monitoring output current and the input voltage. Connected in series to the 3.3 V rail, it is able to protect the electronic circuitry on its output from overcurrent and overvoltage. The STEF033 has controlled delay and turn-on time. When an overload condition occurs, the device 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 the power is re-applied the E-fuse initially limits the output current to a safe value and then goes again into the open state. The voltage clamping circuit prevents the output voltage from exceeding a fixed value, if the input voltage goes beyond this threshold. The device is equipped with a thermal protection circuit. Intervention of thermal protection is signaled to the board-monitoring circuits through an appropriate 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 performances following short-circuit/thermal protection intervention and is reset either by re-cycling the supply voltage or using the appropriate Enable pin. The STEF033 is also available in an auto-retry version; in case of thermal fault it automatically attempts to re-apply power to the load when the die temperature returns to a safe value.

Continuous current typ.: 3.6 A (DFN), 2.5 A (Flip Chip)

N-channel on resistance (typ): 40 m? (DFN), 25 m? (Flip Chip)

Enable/Fault functions

Output clamp voltage (typ): 4.5 V

Undervoltage lockout

Short-circuit limit

Overload current limit

Controlled output voltage ramp

Thermal latch (typ): 160 °C

Uses tiny capacitors

Latching and auto-retry versions

Operative junction temp. - 40 °C to 125 °C

Available in DFN10 3x3 and Flip Chip 9 bumps