Hot swap controller with latched fault — what it does and where it fits
The LTC4231IMS-1#PBF is a single-channel hot swap controller from Analog Devices that manages board-level inrush current and protects against overcurrent, overvoltage, and undervoltage faults on supply rails from 2.7 V to 36 V. It drives an external N-channel MOSFET to soft-start the load, limiting the surge into bulk capacitance during insertion. The controller draws only 4 µA of supply current, making it suitable for always-on or battery-backed backplane slots where every microamp matters. Programmable features — circuit breaker threshold, current limit, fault timeout, overvoltage protection (OVP), undervoltage lockout (UVLO), and slew rate — let the designer tailor the protection envelope to the specific load capacitance and rail tolerance without changing the bill of materials.
Active lifecycle and ROHS compliance — no obsolescence risk
LTC4231IMS-1#PBF carries an Active product status with ROHS3 compliance. No second-source alternate is required for supply assurance at this stage, though the LTC4231IUD-1#PBF (same function, different package) provides a drop-in alternative if board-space constraints change.
12-MSOP package — layout and thermal notes
The part is supplied in a 12-lead MSOP (12-MSOP) package, 3.00 mm wide, surface-mount. The MSOP footprint is compact enough for dense backplane cards but still hand-solderable with a fine-tip iron. No internal switch means the external N-channel MOSFET handles all the power dissipation; the controller itself stays cool. The -40°C to 85°C operating range covers most industrial and telecom indoor environments. For extended-temperature applications (up to 125°C), the LTC4231HUD-1#PBF is the high-temp sibling.