Features

• Ideal Diode and Inrush Current Control for Redundant Supplies
• Low Loss Replacement for Power Schottky Diode
• Protects Output Voltage from Input Brownouts
• Allows Safe Hot Swapping from a Live Backplane
• 2.9V to 18V Operating Range
• Controls Back-to-Back N-Channel MOSFETs
• Limits Peak Fault Current in ≤1μs
• Adjustable Current Limit with Foldback
• Adjustable Start-Up and Current Limit Fault Delay
• 0.5μs Ideal Diode Turn-On and Turn-Off Time
• Undervoltage and Overvoltage Protection
• Status, Fault and Power Good Outputs
• Pin Selectable Latch Off or Automatic Retry After Fault
• 24-Lead 4mm × 5mm QFN and SSOP Packages

Typical Application

Description

The LTC®4229 offers ideal diode and Hot Swap™ functions for a power rail by controlling two external N-channel MOSFETs. The MOSFET acting as an ideal diode replaces a high power Schottky diode and the associated heat sink, saving power and board area. The Hot Swap MOSFET control allows a board to be safely inserted and removed from a live backplane by limiting inrush current. The supply output is also protected against short-circuit faults with a fast acting foldback current limit and electronic circuit breaker.

The LTC4229 regulates the forward voltage drop across the external MOSFET to ensure smooth current transfer in diode-OR applications. The ideal diode turns on quickly to reduce the load voltage droop during supply switchover. If the input supply fails or is shorted, a fast turn-off minimizes reverse-current transients.

The LTC4229 provides adjustable start-up delay, undervoltage and overvoltage protection, and reports fault and power good status for the supply. It can be configured for latch off or automatic retry after a fault.