What the MAX5900AAEUT does and where it fits
The MAX5900AAEUT is a single-channel hot-swap controller from Maxim Integrated's Simple Swapper™ series, designed to manage inrush current and protect downstream loads during board insertion into a live backplane. Its supply range of -9V to -100V targets -48V telecom rectifiers, -72V central-office battery plants, and other high-voltage negative-rail systems common in networking infrastructure. The controller operates from -40°C to 85°C, covering indoor telecom shelters and industrial cabinets where ambient temperature stays within that band.
Protection features — what you can program
The MAX5900AAEUT integrates programmable fault handling: auto retry or latched fault on overcurrent, an adjustable circuit-breaker threshold, current limit, fault timeout, and slew-rate control to shape the inrush profile. Undervoltage lockout (UVLO) holds the external N-channel FET off until the supply rail is within specification. Because the controller has no internal switch, the designer selects the external MOSFET sized for the load current and thermal budget — common in high-current line cards where the pass element must be matched to the dissipation.
Supply current and thermal considerations
Quiescent supply current is 500 µA, which keeps the controller's own dissipation negligible even in always-on power-distribution sections. The SOT-23-6 package (supplier device package SOT-23-6) is surface-mount and fits dense PCB layouts typical of blade servers and line cards. No heatsinking is needed for the controller itself — the external MOSFET handles the load current.
Lifecycle and sourcing
It is RoHS non-compliant per the manufacturer's declaration, so verify your assembly house's exemption policy if the build requires RoHS conformance.