STMicroelectronics STEF05LAPUR

Overview

STEF05LAPUR from STMicroelectronics is a latching-type electronic fuse (eFuse) designed for 5 V rail protection in high-reliability storage systems. It integrates an N-channel power MOSFET with 40 mΩ typical R_DS(on) (DFN10 package), 3.6 A continuous current rating, 6.1 V output clamping voltage, and thermal latch at 160 °C. Used in SSDs and HDD arrays to replace mechanical fuses, it provides programmable current limiting via external resistor and controlled soft-start via dv/dt pin.

For engineers reviewing the STEF05LAPUR datasheet, STEF05LAPUR pinout, STEF05LAPUR application, or STEF05LAPUR equivalent, this page delivers verified electrical specs, DFN10 package layout, thermal shutdown behavior, auto-retry functionality, and real-world use cases in 5 V power path protection for solid-state and rotating media subsystems.

Technical Context

The STEF05LAPUR implements a precision current-sense architecture using an internal N-channel sense FET with fixed ratio to monitor load current and enforce dual-level protection: overload trip-point (ILim = 2.5 A) and short-circuit limit (IShort ≈ 1.2 A with 24 Ω R_Limit). Its integrated dv/dt control circuit enables user-adjustable output voltage ramp-up (1.4–16 ms) via external capacitor on the Cdv/dt pin.

Thermal protection operates with a latched shutdown at 160 °C junction temperature and includes fault signaling via tri-state Enable/Fault pin - pulled to intermediate voltage (0.8–2.0 V) during thermal events. The device supports Kelvin sensing in Flip Chip variants but STEF05LAPUR uses DFN10 with standard source connection and requires no external sense resistor routing.

Key Specifications

Pinout & Package

STEF05LAPUR is supplied in DFN10 (3 × 3 mm) package with exposed thermal pad (VCC). Pin numbering follows top-view marking orientation per DS11527 Rev 2 Figure 2.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TCKE805L, STEF05LAPUR offers superior thermal resilience and field-programmable ramp control; versus TPS25942L, it delivers deterministic analog fault signaling without MCU overhead - ideal for legacy storage controllers lacking I²C support.

Availability

STEF05LAPUR is available at Aetrix Electronics and suitable for solid-state drive (SSD) power management, hard disk drive (HDD) actuator protection, and optical disc drive (ODD) spindle control requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for STEF05LAPUR 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, specializing in power management, automotive ICs, and industrial microcontrollers with over 40 years of analog design heritage.

The STEF series targets high-availability 5 V power path protection in storage subsystems, emphasizing robustness against repetitive overloads, precise current limiting, and seamless integration into legacy and next-generation drive architectures.

FAQ

What is the difference between STEF05LAPUR and STEF05LPUR?

STEF05LAPUR features auto-retry thermal shutdown: after die temperature drops below hysteresis (~135 °C), it automatically restores output without cycling V_CC. STEF05LPUR uses latching shutdown - output remains off until V_CC is cycled or the EN pin is pulsed low-high. Both share identical R_DS(on), current ratings, and pinout in DFN10.

Can the dv/dt pin be left unconnected?

Yes - leaving the dv/dt pin open results in a nominal 1.4 ms output voltage ramp time (10 % to 90 % V_OUT). An external capacitor (0–1 nF) may be added to extend ramp time up to 16 ms. Do not connect dv/dt to GND or V_CC; floating is the default functional state.

How is current limit set, and what resistor value gives 2.5 A overload protection?

Current limit is set by an external resistor (R_Limit) between I-Lim+ (Pin 7) and V_OUT/Source (Pins 1–5). For 2.5 A overload trip-point (I_Lim), DS11527 Figure 12 specifies R_Limit ≈ 24 Ω. Short-circuit limit (I_Short) under same condition is ~1.2 A, confirmed in Table 6.

Does STEF05LAPUR require a heatsink on the PCB?

No dedicated heatsink is needed. The DFN10 package's exposed V_CC pad must be soldered to ≥100 mm² of inner-layer or bottom-side copper pour with ≥4 thermal vias (0.3 mm diameter) to achieve the specified 70 °C/W R_thJA. This satisfies thermal requirements up to 3.6 A continuous load at 25 °C ambient.