STMicroelectronics: Electronic fuse for 5 V line

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 STEF05 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 signaled 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 Efuse 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.

Features:

• Continuous current (typ): 3.6 A
• N-channel on-resistance (typ): 40 mΩ
• 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) package

Applications:

• Solid state drives (SSD)
• SSD arrays

Datasheet: STEF05