Electronic fuse for 3.3 V 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.

Key Features

  • Continuous current typ.: 3.6 A (DFN), 2.5 A (Flip Chip)
  • N-channel on resistance (typ): 40 mΩ (DFN), 25 mΩ (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


Technical Documentation

Product Specifications
Description Version Size
DS9871 DS9871: Electronic fuse for 3.3 V line 2.0 1 MB

Publications and Collaterals

Selection Guides
Description Version Size
Linear and Switching Voltage Regulators Selection Guide 3.0 370 KB
Support & Community

Sample & Buy

Part Number Package Packing Type Marketing Status Unit Price (US$) * Quantity ECCN (EU) ECCN (US) Country of Origin More info Order from ST Order from Distributors
STEF033PUR DFN10 3X3 Tape And Reel Active 0.596 1000 NEC EAR99 CHINA MORE INFO Get Sample Add to cart DISTRIBUTOR AVAILABILITY
STEF033APUR DFN10 3X3 Tape And Reel Active 0.596 1000 NEC EAR99 CHINA MORE INFO No availability reported, please contact our Sales office

(*) Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office  or our Distributors

Quality & Reliability

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
STEF033PUR ActiveDFN10 3X3 IndustrialEcopack2 0 0
STEF033APUR ActiveDFN10 3X3 IndustrialEcopack2

(**) The Material Declaration forms available on st.com may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.