LTC4253 Datasheet | Linear Technology

LTC4253/LTC4253A - 48V Hot Swap Controllers with Sequencer Features n Allows Safe Board Insertion and Removal from a Live - 48V Backplane n Floating Topology Permits Very High Voltage Operation n Adjustable Analog Current Limit with Breaker Timer Ideal for Two Battery Feeds n Fast Response Time Limits Peak Fault Current n Adjustable Undervoltage/Overvoltage Protection with ±1% Threshold Accuracy (LTC4253A) n Three Sequenced Power Good Outputs n Adjustable Soft-Start Current Limit n Adjustable Timer with Drain Voltage Accelerated Response n Latchoff After Fault n Available in a 16-Pin SSOP Package APPLICATIONS n - 48V Distributed Power Systems n Negative Power Supply Control n Central Office Switching n High Availability Servers n Disk Arrays L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. DESCRIPTION The LTC®4253/LTC4253A negative voltage Hot Swap™ controllers allow a board to be safely inserted and removed from a live backplane. Output current is controlled by three stages of current-limiting: a timed circuit breaker, active current limiting and a fast feedforward path that limits peak current under worst-case catastrophic fault conditions. The LTC4253/LTC4253A latch off after a circuit fault. Adjustable undervoltage and overvoltage detectors disconnect the load whenever the input supply exceeds the desired operating range. The LTC4253/LTC4253A’s supply input is shunt-regulated, allowing safe operation with very high supply voltages. A multifunction timer delays initial start-up and controls the circuit breaker’s response time. The circuit breaker’s response time can be accelerated by sensing excessive MOSFET drain voltage, keeping the MOSFET within its safe operating area (SOA). An adjustable soft-start circuit controls MOSFET inrush current at start-up. Three power good outputs are...