What this ORing controller does in a -48V backplane
The LTC4371IDD#PBF is an N+1 ORing controller from Analog Devices, designed to replace power Schottky diode-OR arrays in -48V distributed power systems and AdvancedTCA® shelves. It drives an external N-channel MOSFET to create a low-loss ideal-diode path between redundant supply feeds. The controller itself draws only 300 µA from a local 4.5V to 16V bias rail — it does not run off the -48V bus directly.
The 4.5V to 16V supply range means you need a separate bias supply (e.g., a small isolated DC-DC or a linear regulator off the -48V input). This is common in telecom designs, but if your board lacks a local 12V rail, budget for a bias converter. The 2:1 input-to-output ratio means the controller can manage two input feeds (e.g., two -48V rectifier shelves) and steer the higher voltage to the output. No internal switch — the external N-channel MOSFET handles the current path, so the Rds(on) and thermal design are in your hands.
Package and layout — the 10-DFN exposed pad
The LTC4371IDD#PBF comes in a 10-lead WFDFN with exposed pad, 3x3 mm body (supplier device package 10-DFN). The 0.50 mm pitch demands careful solder paste stencil design; a 4-layer board with a solid ground plane under the pad is the standard approach.