4V to 80V — one controller for 12V, 24V, and 48V rails
The LTC4359IS8#PBF is an N-channel N+1 ORing controller from Analog Devices that replaces a power Schottky diode with a low-Rds(on) MOSFET to reduce forward drop and heat in redundant power architectures. Its 4V to 80V supply range lets a single BOM line cover 12V automotive, 24V industrial, and 48V telecom backplane rails without a separate pre-regulator or supply-rail divider.
300 ns off-delay — why it matters for the MOSFET
The 300 ns turn-off delay is the headline protection spec. When the input rail dips or shorts, the controller must pull the MOSFET gate low before reverse current flows from the output capacitor back through the FET body diode. A 300 ns window means the external MOSFET's SOA at the rail voltage must survive that interval at the fault current — a 60V-rated FET on a 48V rail has roughly 2× derating, which is comfortable. The 200 µs turn-on delay prevents cross-conduction during power-up when multiple supplies are ramping; the controller waits until the input is stable before enabling the FET.
The ROHS3 compliance is confirmed.
Package and temperature grade
That covers most indoor telecom and industrial enclosures; for under-hood automotive or outdoor base stations that see 105°C+ ambient, the LTC4359HMS8#PBF variant extends to 125°C. The 150 µA supply current is the quiescent draw — negligible in a 10A+ ORing path, but worth noting for always-on battery-backed supplies where every microamp counts.