STEF4S:Electronic fuse for 3.3V and 5V lines

The STEF4S is an integrated electronic fuse optimized for monitoring the output current and the input voltage. It can be connected in series to 3.3 V or 5 V rails, protecting the electronic circuitry on its output from overcurrent and overvoltage. The operating mode (5 V or 3.3 V) can be selected by a dedicated pin. The STEF4S has a controlled turn-on time, adjustable by an external capacitor. 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, the E-fuse limits the output current to a safe value.

In case of overvoltage on the input, the device clamps the output voltage to a predefined value and protects the load.

If the anomalous fault condition persists, the internal thermal protection circuit shuts down the device and then automatically attempts to re-supply the load until the fault condition is removed.

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.

Key Features

  • Power MOSFET on-resistance (typ.): 40 mΩ
  • Enable function
  • Output clamp voltage (typ.): 5.7 V in 5 V mode, and 3.8 V in 3.3 V mode
  • Undervoltage lockout
  • Short-circuit limit
  • Overload foldback current limit
  • Controlled soft-start
  • Thermal auto-retry
  • Internal sensing FET
  • Operative temp. range: - 40 °C to 85 °C
  • Available in DFN 3x3 10L package
  • Hard disk drives
  • Solid state drives (SSD)
  • Hard disk and SSD arrays
  • Set-top boxes
  • DVD and blu-ray disc drivers
Product Specifications
DescriptionVersionSize
DS9933: Electronic fuse for 3.3 V and 5 V lines2.0635 KB
Selection Guides
DescriptionVersionSize
Linear and Switching Voltage Regulators Selection Guide383 KB
Sample & Buy
Part NumberPackagePacking TypeUnit Price (US$) *QuantityECCN (EU)ECCN (US)Country of Origin
STEF4SPURVFDFPN 10 3x3x0.75Tape And Reel0.9541000NECEAR99CHINA
Quality & Reliability
Part NumberPackageGradeRoHS Compliance GradeMaterial Declaration**
STEF4SPURVFDFPN 10 3x3x0.75IndustrialEcopack2md_wv-wspc-sot23-wspc-5l_mfwvrr33fc1.pdf
md_wv-wspc-sot23-wspc-5l_mfwvrr33fc1.xml
Electronic fuse for 3.3 V and 5 V lines STEF4S
Digital controller for wireless battery charger transmitters for wearable and smartwatch applications STWBC-WA
md_wv-wspc-sot23-wspc-5l_mfwvrr33fc1.pdf STEF4S
md_wv-wspc-sot23-wspc-5l_mfwvrr33fc1.xml STEF4S