LTC4227-1/LTC4227-2 - Dual Ideal Diode and Single Hot Swap Controller - Linear Technology - #1

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LTC4227-1/LTC4227-2 1 422712f Typical Application Features Description Dual Ideal Diode and Single Hot Swap Controller The LTC®4227 offers ideal diode and Hot Swap™ functions for two power rails by controlling external N-channel MOSFETs. MOSFETs acting as ideal diodes replace two high power Schottky diodes and the associated heat sinks, saving power and board area. A Hot Swap control MOSFET 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 current limit and internal timed circuit breaker. The LTC4227 regulates the forward voltage drop across the MOSFETs to ensure smooth current transfer from one supply to the other without oscillation. The ideal diodes turn 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 LTC4227 allows turn-on/off control, and reports fault and power good status for the supply. The LTC4227-1 features a latch-off circuit breaker, while the LTC4227-2 provides automatic retry after a fault. Diode-OR with Hot Swap Application Applications n Power Path and Inrush Current Control for Redundant Supplies n Low Loss Replacement for Power Schottky Diodes n Allows Safe Hot Swapping from a Live Backplane n 2.9V to 18V Operating Range n Controls N-Channel MOSFETs n Limits Peak Fault Current in 1ìs n 0.5ìs Turn-On and Reverse Turn-Off Time n Adjustable Current Limit with Circuit Breaker n Smooth Switchover without Oscillation n Adjustable Current Limit Fault Delay n Fault and Power Status Output n LTC4227-1: Latch Off After Fault n LTC4227-2: Automatic Retry After Fault n 20-Lead 4mm × 5mm QFN and 16-Lead SSOP Packages n Redundant Power Supplies n Supply Holdup n Computer Systems and Servers n Telecom Networks L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. BACKPLANE CONNECTOR 12V 12V CARD CONNECTOR CPO1 D2ON ON FAULT PWRGD 137k 100ìF 12V 7.6A 20k INTVCC GND IN1 DGATE1 DGATE2 LTC4227 422712 TA01a SiR462DP 0.006 Si7336ADP CPO2 SENSE+ SENSE– HGATE OUT 0.1ìF IN2 + 0.1ìF SiR462DP EN 0.1ìF 0.1ìF TMR Power Dissipation vs Load Current LOAD CURRENT (A) 0 0 POWER DISSIPATION (W) 0.5 1.0 1.5 2.0 2.5 3.0 2 4 6 8 4227 TA01 DIODE (SBG1025L) MOSFET (SiR462DP) POWER SAVED