Overview
The STEF4SPUR, produced by STMicroelectronics, is an integrated electronic fuse designed to monitor and protect electronic circuits from overcurrent and overvoltage conditions. This device is optimized for use on 3.3 V and 5 V power lines and offers a range of protective features, including undervoltage lockout, short-circuit limit, overload foldback current limit, and thermal auto-retry. The STEF4SPUR can be connected in series to the power rails, ensuring the load is protected from anomalous conditions without the need for physical replacement after an event, unlike traditional mechanical fuses.
Key Specifications
| Parameter | Typical Value | Unit |
|---|---|---|
| Operating Input Voltage | 3.3 V / 5 V | V |
| Output Clamping Voltage (3.3 V mode) | 3.8 V | V |
| Output Clamping Voltage (5 V mode) | 5.7 V | V |
| Power MOSFET On-Resistance | 40 mΩ | mΩ |
| Current Limit | 5 A | A |
| Overload Current Limit | 5 - 9 A | A |
| Short-Circuit Current Limit | 3 A | A |
| Operating Temperature Range | -40 °C to 85 °C | °C |
| Package Type | DFN 3x3 - 10L |
Key Features
- Enable function with active high enable pin
- Undervoltage lockout (UVLO) with adjustable thresholds
- Short-circuit and overload protection with foldback current limit
- Controlled soft-start with adjustable startup time using an external capacitor
- Thermal auto-retry mechanism for continuous fault condition handling
- Internal sensing FET for accurate current monitoring
- Output voltage clamping to protect against overvoltage
Applications
- Hard disk drives
- Solid state drives (SSD)
- Hard disk and SSD arrays
- Set-top boxes
- DVD and Blu-ray disc drivers
Q & A
- What is the STEF4SPUR used for? The STEF4SPUR is used to protect electronic circuits from overcurrent and overvoltage conditions on 3.3 V and 5 V power lines.
- How does the STEF4SPUR protect against overcurrent? The device limits the output current to a predefined safe value during an overload condition and goes into an open state if the condition persists.
- What is the typical on-resistance of the power MOSFET in the STEF4SPUR? The typical on-resistance is 40 mΩ.
- How can the operating mode of the STEF4SPUR be selected? The operating mode (3.3 V or 5 V) can be selected using the VCP pin.
- What is the purpose of the soft-start feature in the STEF4SPUR? The soft-start feature allows for a controlled turn-on time, adjustable by an external capacitor, to prevent inrush currents.
- Does the STEF4SPUR degrade after short-circuit or thermal protection interventions? No, unlike mechanical fuses, the STEF4SPUR does not degrade in its performance after such interventions.
- What is the operating temperature range of the STEF4SPUR? The operating temperature range is -40 °C to 85 °C.
- How does the thermal auto-retry mechanism work? If a 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.
- What package type is the STEF4SPUR available in? The STEF4SPUR is available in a DFN 3x3 - 10L package.
- Can the startup time of the STEF4SPUR be adjusted? Yes, the startup time can be adjusted by connecting a capacitor between the SST pin and GND.
