Analog Devices Inc./Maxim Integrated

The LTC4224 Dual Low Voltage Hot Swap™controller allows a board to be safely inserted and removed from a live backplane. It controls two supplies with external N-channel MOSFETs and operates with one supply as low as 1V provided the other supply is 2.7V or greater. The LTC4224 can ramp up the supplies in any order and at adjustable ramp rates. To minimize the number of external components and PCB area, the gate capacitor is optional, all timing delays are generated internally, and theONpins have integrated pull-up currents.Protection against overcurrent faults is provided by a fast-acting current limit and timed circuit breakers. AFAULTpin signals overcurrent faults. The LTC4224-1 remains off after a fault, while the LTC4224-2 automatically tries to apply power again after a four second cool-down period.ApplicationsOptical NetworkingLow Voltage Hot SwapElectronic Circuit Breakers

The LTC4226 dual Hot Swap™controller allows two power paths to be safely inserted and removed from a live backplane or powered connector. Using N-channel pass transistors, supply voltages ranging from 4.5V to 44V are ramped up at an adjustable rate.Three selectable ratios of current limit to circuit breaker threshold accommodate noisy loads and momentary high peak currents without interruption, while a dual-rate fault timer protects the MOSFET from extended output overcurrent events.FAULToutputs indicate the circuit breaker status.The LTC4226-1 remains off after a fault while the LTC4226-2 automatically retries after a 0.5s delay.The LTC4226 can also be configured as a bidirectional current limiter/circuit breaker. For high current applications, two channels may be configured as parallel power paths.ApplicationsApple FireWire/IEEE 1394Disk DrivesRugged 12V, 24V ApplicationsHot Board/Connector InsertionUni/Bidirectional Current Limiter/Circuit Breaker

The LTC4227 offers ideal diode-OR and Hot Swap™functions for two power rails by controlling external Nchannel 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.PartOvercurrent FaultStart-Up DelayLTC4227-1Latch Off100msLTC4227-2Retry100msLTC4227-3Latch Off1.6msLTC4227-4Retry1.6msApplicationsRedundant Power Supplies and Supply HoldupComputer Systems and ServersTelecom Networks

The LTC4229 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.ApplicationsRedundant Power SuppliesSupply HoldupHigh Availability Systems and ServersTelecom and Network InfrastructurePower Prioritizer

The LTC4232-1 is an integrated solution for Hot Swap applications that allows a board to be safely inserted and removed from a live backplane. The part integrates a Hot Swap controller, power MOSFET and current sense resistor in a single package for small form factor applications.The LTC4232-1 provides separate inrush current control and a 10% accurate 5A current limit with foldback current limiting. The current limit threshold can be adjusted dynamically using an external pin. Additional features include a current monitor output that amplifies the sense resistor voltage for ground referenced current sensing and a MOSFET temperature monitor output. Thermal limit, overvoltage, undervoltage and power good monitoring are also provided.The PCI Express compliant LTC4232-1 allows faster turn-on than the LTC4232 by providing a shorter (16ms) debounce delay and external control of the GATE ramp rate.ApplicationsRAID Systems, Solid State DrivesServer I/O CardsPCI Express SystemsIndustrial

The LTC4232-1 is an integrated solution for Hot Swap applications that allows a board to be safely inserted and removed from a live backplane. The part integrates a Hot Swap controller, power MOSFET and current sense resistor in a single package for small form factor applications.The LTC4232-1 provides separate inrush current control and a 10% accurate 5A current limit with foldback current limiting. The current limit threshold can be adjusted dynamically using an external pin. Additional features include a current monitor output that amplifies the sense resistor voltage for ground referenced current sensing and a MOSFET temperature monitor output. Thermal limit, overvoltage, undervoltage and power good monitoring are also provided.The PCI Express compliant LTC4232-1 allows faster turn-on than the LTC4232 by providing a shorter (16ms) debounce delay and external control of the GATE ramp rate.ApplicationsRAID Systems, Solid State DrivesServer I/O CardsPCI Express SystemsIndustrial