LT4200 Hot Swap E-Fuse

ADI's LT4200 is an integrated solution for hot swap applications that allows a board to be safely inserted and removed from a live backplane. The part integrates a hot swap controller, power MOSFET, and current sense resistor into a single package for small form factor applications. The MOSFET safe operating area is production tested and guaranteed for the stresses in hot swap applications.

The LT4200 allows 50 A of continuous operation at up to +85°C ambient temperature. It provides separate inrush current control and a ±12% accurate 57 A current limit with output-dependent foldback. The current limit threshold can be adjusted dynamically using the ISET pin. Additional features include a current monitor output for ground referenced current sensing and a MOSFET temperature monitor output. Thermal limit, overvoltage, undervoltage, and power good monitoring are also provided.

The demonstration circuit DC3024A showcases the LT4200 50 A hot swap E-fuse with guaranteed SOA. Included on the board are input voltage dividers for undervoltage and overvoltage protection, LEDs to indicate input voltage, output voltage, fault and power bad conditions, and jumpers to enable auto retry and to select circuit breaker delay. Turrets are provided for monitoring input voltage, output voltage, output status, and most of the pins on the LT4200.

Features

• MOSFET SOA guarantees protection and reliability during hot swap stresses, including start-up inrush and current limiting
• Integrated MOSFET simplifies design and reduces solution size
• 28 V abs max voltage rating on supply pin has better chance of surviving any transients beyond the 15 V max operating voltage