Features

• Allows Safe Insertion into Live Backplane
• 8-Bit ADC Monitors Current and Voltage
• I²C/SMBus Interface
• Wide Operating Voltage Range: 2.9V to 15V
• Adjustable Overcurrent Filter Time
• High Side Drive for External N-Channel MOSFET
• No External Gate Capacitor Required
• Input Overvoltage/Undervoltage Protection
• Optional Latchoff or Auto-Retry After Faults
• Alerts Host After Faults
• Inrush Current Limit with Foldback
• Available in 24-Pin 4mm x 5mm QFN Package

Typical Application

Description

The LTC4280 Hot Swap controller allows a board to be safely inserted and removed from a live backplane. Using an external N-channel pass transistor, board supply voltage and inrush current are ramped up at an adjustable rate. An I²C interface and onboard ADC allow for monitoring of load current, voltage and fault status.

The device features adjustable analog foldback current limit and a FILTER pin which configures the time spent in overcurrent before declaring a fault. An I²C interface may configure the part to latch off or automatically restart after the LTC4280 detects a current limit fault.

The controller has additional features to interrupt the host when a fault has occurred, notify when output power is good, detect insertion of a load card, and power-up either automatically upon insertion or wait for an I²C command to turn on.