This document introduces the LTC4223 hot swap solution for Advanced Mezzanine Card design. The solution provides inrush control, overcurrent protection and supply monitoring, can detect board insertion and extraction, in order to provide 12V and 3.3V auxiliary power supply in a controlled manner without damaging the connector. LTC4223 also provides a current monitor output for the 12V supply, allowing real-time current monitoring. Short-circuit faults on the 12V and 3.3V output are rapidly isolated.
The LTC4223 offers a compact and comprehensive Hot Swap solution for Advanced Mezzanine Cards (AdvancedMC), providing inrush control, overcurrent protection, and supply monitoring. It detects board insertion and extraction to protect the connector while delivering 12V and 3.3V auxiliary power supplies in a controlled manner.
The device features an adjustable current limit with circuit breaker function for the external MOSFET on the 12V supply and protects the internal 3.3V switch via thermal shutdown. It includes high-side current sense monitoring, auto-retry functionality (for LTC4223-2), and ignores contact bounces during card insertion.
The AUXPGOOD output pulls low when the auxiliary supply exceeds 2.901V, and the 12PGOOD output pulls low when the 12V supply exceeds 10.36V.
The internal 3.3V auxiliary supply switch shuts off immediately if its temperature reaches 150°C.
All switches are turned off in 20s when the EN pin indicates that the card has been removed.