Features

• Allows Safe Board Insertion and Removal from a Live Backplane
• Controls Supply Voltages from 2.5V to 16.5V
• Programmable Soft-Start with Inrush Current Limiting, No External Gate Capacitor Required
• Faster Turn-Off Time Because No External Gate Capacitor is Required
• Dual Level Overcurrent Fault Protection
• Programmable Response Time for Overcurrent Protection (MS)
• Programmable Overvoltage Protection (MS)
• Automatic Retry or Latched Mode Operation (MS)
• High Side Drive for an External N-Channel FET
• User-Programmable Supply Voltage Power-Up Rate
• FB Pin Monitors V_OUT and Signals RESET
• Glitch Filter Protects Against Spurious RESET Signal

Typical Application

Description

The LTC4211 is a Hot Swap controller that allows a board to be safely inserted and removed from a live backplane. An internal highside switch driver controls the gate of an external N-channel MOSFET for supply voltages ranging from 2.5V to 16.5V. The LTC4211 provides soft-start and in rush current limiting during the start-up period which has a programmable duration.

Two on-chip current limit comparators provide dual level overcurrent circuit breaker protection. The slow comparator trips at V_CC – 50mV and activates in 20µs (or programmed by an external filter capacitor,MS only). The fast comparator trips at V_CC – 150mV and typically responds in 300ns.

The FB pin monitors the output supply voltage and signals the RESET output pin. The ON pin signal turns the chip on and off and can also be used for the reset function. The MS package has FAULT and FILTER pins to provide additional functions like fault indication, autoretry or latch-off modes, programmable current limit response time and programmable overvoltage protection using an external Zener diode clamp.