LT1640A Datasheet

• Allows Safe Board Insertion and Removal from a Live -48V Backplane
• Operates from -10V to -80V
• Programmable Inrush Current
• Allows 50mA of Reverse Drain Pin Current
• Programmable Electronic Circuit Breaker
• Programmable Overvoltage Protection
• Programmable Undervoltage Lockout
• Power Good Control Output

• Central Office Switching
• -48V Distributed Power Systems
• Negative Power Supply Control

The LT1640AL/LT1640AH are 8-pin, negative voltage Hot Swap^™ controllers that allow a board to be safely inserted and removed from a live backplane. Inrush current is limited to a programmable value by controlling the gate voltage of an external N-channel pass transistor. The pass transistor is turned off if the input voltage is less than the programmable undervoltage threshold or greater than the overvoltage threshold. A programmable electronic circuit breaker protects the system against shorts. The PWRGD (LT1640AL) or PWRGD (LT1640AH) signal can be used to directly enable a power module. The LT1640AL is designed for modules with a low enable input and the LT1640AH for modules with a high enable input.

The LT1640AL/LT1640AH are available in 8-pin PDIP and SO packages.