9 V to 72 V supply — the fit for 48 V and 24 V backplanes
The MAX5902ACEUT+T is a single-channel hot swap controller from Analog Devices' Simple Swapper™ family, designed to manage the inrush current and protect against faults when a card is inserted into a live backplane. Its 9 V to 72 V supply range covers both 48 V telecom and 24 V industrial rails without needing a separate regulator for the controller's own power. The controller draws 1 mA from the rail — its own consumption is negligible next to the load current it manages, so the thermal budget for the controller itself is not a concern in most line-card layouts.
Protection scheme — fault timeout, latched fault, thermal limit
Three protection features are built in: a fault timeout that limits the duration of an overcurrent event, a latched fault that keeps the external pass FET off after a fault until the input is cycled or the UVLO pin is toggled, and a thermal-limit circuit that shuts down the controller if the die temperature exceeds the safe operating area. No internal switch is included — the controller drives the gate of an external N-channel MOSFET, which the designer selects for the peak current and Rds(on) the load demands. The undervoltage lockout threshold is programmable via a resistor divider on the UVLO pin, letting the system designer set the minimum input voltage at which the controller enables the pass FET. This prevents the card from drawing current until the backplane voltage is stable.
SOT-23-6 package and industrial temperature range
The MAX5902ACEUT+T comes in a 6-lead SOT-23 package (also designated SOT-6), occupying minimal board area on a dense line card. The surface-mount footprint is standard and well-documented in the datasheet's layout guidelines. No derating is required for the controller itself within this band, though the external pass FET's Rds(on) increase with temperature must be factored into the thermal design.
The part is tape-and-reel packaged (also available in cut tape) for automated pick-and-place assembly.