STMicroelectronics STEF05PUR

Overview

STEF05PUR from STMicroelectronics is a 5 V electronic fuse IC featuring N-channel MOSFET architecture with 40 mΩ typical on-resistance, 3.6 A continuous current rating, 6.65 V output clamping voltage, and thermal latch at 165 °C. It operates in series with a 5 V rail to protect downstream circuitry in storage subsystems against overcurrent, short-circuit, overvoltage, and thermal faults.

For engineers reviewing the STEF05PUR datasheet, STEF05PUR pinout, STEF05PUR application, or STEF05PUR equivalent, key selection criteria include controlled dv/dt ramp-up time (~1 ms), tri-state Enable/Fault signaling for thermal fault detection, and external R_LIMIT-programmable current thresholds (e.g., 2.9 A overload, 2.9–3.9 A short-circuit limit).

Technical Context

The STEF05PUR integrates a precision N-channel power MOSFET with internal current-sense FET, UVLO (3.2–4.0 V turn-on), output voltage clamp, and thermal shutdown circuitry. Its Enable/Fault pin functions as both control input and fault status indicator-floating enables operation, grounding disables output, and intermediate voltage (0.82–1.95 V) signals thermal latch activation.

Current limiting is set by an external resistor (R_LIMIT) between I-Limit and Source pins, enabling programmable short-circuit (e.g., 2.9 A @ 22 Ω) and overload thresholds. The dv/dt pin controls output voltage slew rate via internal capacitance or optional external capacitor, supporting soft-start into capacitive or shorted loads.

Key Specifications

Pinout & Package

STEF05PUR is housed in a thermally enhanced DFN10 (3 × 3 mm) package with exposed VCC pad for improved heat dissipation. The 10-terminal layout includes five Source pins (1–5) paralleled for low-inductance, high-current path routing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TCKE205A and TPS259211, STEF05PUR delivers optimal balance of analog simplicity, thermal coordination, and soft-start precision for 5 V storage and consumer electronics - requiring no programming, minimal external components, and direct fault visibility.

Availability

STEF05PUR is available at Aetrix Electronics and suitable for hard disk drives, solid state drives, and set-top boxes requiring stable component supply, long-term lifecycle support, and production-ready qualification.

Supply support for STEF05PUR 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 silicon solutions for automotive, industrial, and consumer markets since 1987.

The STEF series targets high-reliability power distribution in storage and multimedia systems, emphasizing resettable protection, thermal coordination, and analog-programmable current limits without digital overhead.

FAQ

What is the recommended PCB layout for thermal performance?

Mount STEF05PUR on a minimum 0.5 in² copper pour connected to the exposed VCC pad via ≥6 thermal vias (0.3 mm diameter). Route Source pins (1–5) with ≥15 mil traces and keep I-Limit and dv/dt traces short and noise-isolated. Avoid placing thermal relief on VCC pad to maximize heat transfer to inner layers.

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

During thermal latch activation, the En/Fault pin transitions from high state (>1.96 V) to a stable intermediate voltage (0.82–1.95 V) that can directly drive a microcontroller GPIO configured as analog input or comparator. This state persists until VCC is cycled or the pin is pulsed low then released.

Can STEF05PUR be used on a 3.3 V rail?

No - STEF05PUR requires minimum 3.2 V UVLO turn-on and is rated for 5 V nominal operation. Its 6.65 V output clamp and 3.6 A current rating are optimized for 5 V systems. For 3.3 V rails, ST recommends STEF03 (not pin-compatible) or alternative eFuses with lower V_CLAMP and UVLO thresholds.

What determines the short-circuit current limit value?

The short-circuit current limit is set by the resistor (R_LIMIT) between pins 7 (I-Limit) and 1–5 (Source). At 22 Ω, it delivers 2.9 A typical short-circuit limit. The relationship is inverse and nonlinear - see Figure 13 in ST's Doc ID 019055 Rev 5 for exact R_LIMIT vs. I_SHORT curves across temperature.