What the MAX5903NNETT+T is and where it fits
The Maxim Integrated MAX5903NNETT+T is a single-channel hot swap controller from the Simple Swapper™ series, designed to manage inrush current and protect downstream circuitry during board insertion into a live backplane. Its 9V to 72V supply range covers the common telecom -48V rail, 24V industrial buses, and 12V automotive systems, making it a general-purpose choice for any application where a board must be plugged into a powered slot without glitching the shared supply. The controller does not integrate the pass switch — it drives an external N-channel MOSFET, so the current rating scales with the FET you pair it with.
Key ratings and what they mean for the BOM
The 9V to 72V input range is the primary selection gate: a 48V telecom design sees plenty of headroom for transients, while a 12V automotive board still has margin above the nominal rail. The 1 mA supply current is the controller's own draw, negligible against the load current the external FET handles — it matters for standby power budgets but not for the main thermal calculation. Programmable UVLO lets you set the undervoltage lockout threshold with a resistor divider, so the controller stays off until the input rail is stable, preventing the FET from turning on during a brownout. The thermal limit feature protects the external FET by latching off if the die temperature exceeds the threshold — a useful safeguard when the load fault is a hard short that the current-limit loop alone cannot clear fast enough.
Package and temperature grade
Housed in a 6-TDFN 3x3 mm exposed pad package, the MAX5903NNETT+T is surface-mount. The exposed pad needs a thermal via stitch to the ground plane. Operating range is -40°C to 85°C.
Lifecycle and sourcing
The MAX5903NNETT+T carries an active lifecycle status and is ROHS3 compliant. For current pricing and availability, submit an RFQ — the quote will reflect the prevailing market conditions at the time of your request. No official second source or pin-compatible alternate is cited in the available records; if dual-sourcing is a requirement, the design should accommodate a functional equivalent from another vendor with a similar UVLO-programmable hot swap controller in the same supply range.