Features
• 15 V typical output overvoltage clamp
• Absolute maximum voltage of 25 V
• Adjustable current limit
• Thermal protection
• Input undervoltage lockout
• Low inrush current during startup
• Integrated 40 mΩ Power FET
• En/fault pin
• Adjustable slew rate for output voltage
• Gate control pin for reverse current blocking FET (DFN10 package)
• TSOT23-8L and DFN10 (3x3 mm) packages
• Latch (STEF12S) or autoretry (STEF12SA) versions

Applications
• Hard Disk and SSD drives
• Hard disk array
• Hot-swap board
• Hot-plug protection

Description
The STEF12S is an integrated electronic fuse optimized to monitor the 12 V DC
power lines.
When connected in series to the main power rail, it is able to precisely detect and
react to overcurrent and overvoltage conditions.
When an overload condition occurs, the device limits the output current to a safe
value defined by the user. If the anomalous overload condition persists, the device
goes into an open state, disconnecting the load from the power supply.
In case of overvoltage on the input, the device regulates the output to a preset safe
value.
Undervoltage lockout prevents the load from malfunction, keeping the device off if the
rail voltage is too low.
The STEF12S features the adjustable turn-on slew-rate, which is useful to keep the
in-rush current under control during startup and hot-swap operations.
On the DFN10 package a dedicated pin provides a gate control for an external
optional N-channel Power FET, used to implement the reverse current blocking in
case of input voltage loss.
The STEF05S is a companion chip for the 5 V rails, useful to implement a complete
power rail control in data-storage applications.