STEF4S Electronic fuse for 3.3 V and 5 V lines Datasheet - production data 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, the E-fuse limits the output current to a safe value. In case of overvoltage on the input, the device clamps the output voltage to a predefined value / )1 and protects the load. If the anomalous 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 Features removed. Power MOSFET on-resistance (typ.): 40 m Unlike mechanical fuses, which must be Enable function physically replaced after a single event, the E- fuse does not degrade in its performance after Output clamp voltage (typ.): 5.7 V in 5 V mode, short-circuit/thermal protection interventions. and 3.8 V in 3.3 V mode Undervoltage lockout Applications Short-circuit limit Hard disk drives Overload foldback current limit Solid state drives (SSD) Controlled soft-start Hard disk and SSD arrays Thermal auto-retry Set-top boxes Internal sensing FET DVD and blu-ray disc drivers Operative temp. range: - 40 C to 85 C Available in DFN 3x3 10L package Table 1. Device summary Order code Package Packing Description STEF4SPUR DFN 3x3 - 10L Tape and reel The STEF4S is an integrated electronic fuse optimized for monitoring the output current and the input voltage. It can be connected in series to 3.3 V or 5 V rails, protecting the electronic circuitry on its output from overcurrent and overvoltage. The operating mode (5 V or 3.3 V) can be selected by a dedicated pin. The STEF4S has a controlled turn-on time, adjustable by an external capacitor. When an overload condition occurs the device limits the output current to a December 2014 DocID025259 Rev 2 1/22 This is information on a product in full production. www.st.comContents STEF4S Contents 1 Block diagram 3 2 Pin configuration 4 3 Maximum ratings 5 4 Electrical characteristics . 6 5 Typical characteristics . 8 5.1 Operating modes 9 5.1.1 Turn-on 9 5.1.2 Normal operating condition . 9 5.1.3 Output voltage clamp 9 5.1.4 Current limiting . 9 5.1.5 Thermal shutdown and auto-retry function . 9 5.2 Startup time and CSS calculation 9 5.3 UVLO and voltage clamp selection . 10 5.4 Enable pin 10 6 Typical performance characteristics . 11 7 Package information 14 7.1 DFN6 3x3 - 10L package information 15 7.2 DFN6 3x3 - 10L packing information 18 8 Revision history . 21 2/22 DocID025259 Rev 2