STMicroelectronics STEF033APUR

Overview

STEF033APUR from STMicroelectronics is a latching/auto-retry electronic fuse optimized for 3.3 V rail protection in high-reliability storage systems. It delivers 3.6 A continuous current (DFN package), features 40 mΩ typical R_DS(on), 4.5 V output clamping, undervoltage lockout at 2.35 V, and thermal latch at 160 °C. Used in SSDs and HDD arrays to prevent overcurrent, short-circuit, and overvoltage damage during hot-plug or fault events.

For engineers reviewing the STEF033APUR datasheet, STEF033APUR pinout, STEF033APUR application, or STEF033APUR equivalent, this page provides verified functional identity, DFN10 package mapping, validated Enable/Fault bidirectional signaling, confirmed soft-start ramp control via dv/dt pin, and real-world current-limiting behavior under I_SHORT and I_LIM conditions.

Technical Context

The STEF033APUR integrates an N-channel power MOSFET with precision current-sensing architecture using an internal Sense FET and external R_LIMIT resistor to set dual-level current protection: 1.35 A short-circuit limit and 2.5 A overload trip point. Its thermal shutdown circuit triggers at 160 °C and-unlike the latching STEF033PUR-automatically retries after die temperature falls below hysteresis (25 °C).

It implements controlled turn-on via internal dv/dt circuitry (1.4 ms default ramp time) and supports user-adjustable slew rate using an external capacitor on the dv/dt pin. The tri-state Enable/Fault pin operates as both input (enable/disable) and open-drain status indicator, sinking intermediate voltage (0.8–1.4 V) during thermal fault to signal host monitoring circuits.

Key Specifications

Pinout & Package

STEF033APUR is housed in a thermally enhanced DFN10 (3 × 3 mm) package with exposed VCC pad (B1–B3) and 10-pin top-side layout. Pin 1–5 are paralleled V_OUT/Source terminals for low-inductance, high-current output routing; pins 6–10 provide discrete control and sensing functions.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar electronic fuse applications.

Compared with STEF033APUR, STEF033PUR offers identical protection specs but mandates external reset after thermal fault, while TCKE805M0L sacrifices clamping, soft-start, and current rating to fit smaller packages-making STEF033APUR optimal for compact, self-recovering 3.3 V storage power rails.

Availability

STEF033APUR is available at Aetrix Electronics and suitable for solid state drives, hard disk drive arrays, and optical disc drive power management requiring stable component supply, long-term lifecycle support, and automotive-grade reliability validation.

Supply support for STEF033APUR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The STEF series targets high-density storage and computing platforms, delivering integrated eFuse functionality with precision current limiting, thermal resilience, and system-level fault signaling to replace discrete protection circuits.

FAQ

What is the function of the dv/dt pin on STEF033APUR?

The dv/dt pin controls the output voltage ramp-up time during turn-on. With no external capacitor, it provides a fixed 1.4 ms rise time (10% to 90% of V_OUT). Adding a capacitor (0–1 nF) between dv/dt and GND extends this to up to 16 ms, enabling inrush current control for sensitive downstream loads like LDOs or large bulk capacitors.

How does the Enable/Fault pin behave during thermal shutdown?

During thermal shutdown, the Enable/Fault pin transitions from high-impedance (normal operation) or low (disabled state) to a defined intermediate voltage range of 0.8–1.4 V. This level is detectable by standard GPIO inputs and can be used to trigger host MCU interrupts or daisy-chain to other STEF devices for synchronized fault response.

Can STEF033APUR replace a mechanical fuse in HDD applications?

Yes-STEF033APUR replaces mechanical fuses with superior performance: it provides repeatable, non-degrading current limiting (3.6 A continuous), fast short-circuit response (<500 µs), and auto-retry recovery without physical replacement. Its 40 mΩ R_DS(on) also minimizes voltage drop versus typical fuse resistance, preserving 3.3 V rail integrity under load.

What is the difference between STEF033APUR and STEF033PUR?

Both share identical electrical specs and DFN10 packaging, but STEF033APUR features auto-retry thermal protection (resets automatically after cooling), whereas STEF033PUR latches off permanently until V_CC is cycled or the Enable pin is toggled. This makes STEF033APUR ideal for unattended storage systems, while STEF033PUR suits supervised industrial controllers.