Analog Devices

The LTC4222 Hot Swap™controller allows two power paths to be safely inserted and removed from a live backplane. Using external N-channel pass transistors, board supply voltages and inrush currents are ramped up at an adjustable rate. An I2C interface and on-board ADC allows for monitoring of current, voltage and fault status for each channel.The device features adjustable, analog, foldback current limit circuits and a Soft-Start circuit that sets the dI/dt of the inrush currents. An I2C interface may configure the part to latch off or automatically restart after the LTC4222 detects a fault on either channel.The controller has additional features to interrupt the host when a fault has occurred, notify when output power is good, detect insertion of a load card and power-up either automatically upon insertion or wait for an I2C command to turn on.ApplicationsLive Board InsertionElectronic Circuit BreakersComputers, ServersPlatform Management

The LTC4223 positive voltage Hot Swap™controller allows a board to be safely inserted and removed from a live AMC or MicroTCA backplane. It controls the main 12V supply with an external N-channel MOSFET and the 3.3V auxiliary supply with an integrated switch. The 12V output ramp rate is adjustable and includes inrush current limiting. The 12V output is also protected against short circuit faults with a fast acting current limit and a 5% accurate timed circuit breaker. The 3.3V output includes both soft start and overcurrent protection.The LTC4223 features a current monitor output for the 12V supply, and reports fault and power-good status for both supplies. It also detects card presence and allows independent control of the 12V and auxiliary 3.3V supply outputs. The LTC4223-1 features a latch-off circuit breaker, while the LTC4223-2 provides automatic retry after a fault.ApplicationsAdvanced Mezzanine Card, MicroTCA SystemsWorkstations and Server I/OTelecom Networks

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 LTC4225 offers ideal diode and Hot Swap™functions for two power rails by controlling external series connected N-channel MOSFETs. MOSFETs acting as ideal diodes replace two high power Schottky diodes and the associated heat sinks, saving power and board area. Hot Swap control MOSFETs allow boards 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 LTC4225 regulates the forward voltage drop across the back-to-back 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 switch-over. If the input supply fails or is shorted, a fast turn-off minimizes reverse-current transients.The LTC4225 allows independent on/off control, and reports fault and power good status for the supply. The LTC4225-1 features a latch-off circuit breaker, while the LTC4225-2 provides automatic retry after a fault.ApplicationsRedundant Power SuppliesSupply HoldupMicroTCA Systems and ServersTelecom NetworksPower Prioritizer

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 LTC4228 offers ideal diode and Hot Swap™functions for two power rails by controlling two external N-channel MOSFETs in each rail. MOSFETs acting as ideal diodes replace two high power Schottky diodes and the associated heat sinks, saving power and board area. Hot Swap control MOSFETs allow boards 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 LTC4228 regulates the forward voltage drop across the external MOSFETs and sense resistor 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 switch-over. If the input supply fails or is shorted, a fast turn-off minimizes reverse-current transients.The LTC4228 allows independent on/off control, and reports fault and power good status for the supply. The LTC4228 improves on the LTC4225 by recovering more quickly from input brownouts to preserve the output voltage.ApplicationsRedundant Power SuppliesMicroTCA Systems and ServersTelecom NetworksPower Prioritizer

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 LTC4230 is a 3-channel Hot Swap™controller that allows a board to be safely inserted and removed from a live backplane. Internal high side switch drivers control the gates of external N-channel MOSFETs for supply voltages ranging from 1.7V to 16.5V. The LTC4230 provides soft-start and inrush current limiting during the programmable start-up period.On-chip current limit comparators provide dual level circuit breaker protection. The slow comparators trip at VCCn– 50mV and activate in 10µs or are programmed by an external filter capacitor. The fast comparators trip at VCCn– 150mV and typically respond in 500ns.Each FBnpin monitors its own output supply voltage and signals itsRESETpin. The ON pin turns the chip on and off and can be used for a reset function. The LTC4230 also provides additional functions including fault indication, autoretry or latchoff modes, programmable current limit response time based on theFAULTand FILTER pins’ functionality.ApplicationsElectronic Circuit BreakerHot Board Insertion and Removal (Either On Backplane or On Removable Card)Industrial High Side Switch/Circuit Breaker

The LTC4231 is a micropower Hot Swap controller that allows safe circuit board insertion and removal from a live power supply. An internal high side switch driver controls the gate of an external N-channel MOSFET. Back-to-back MOSFETs can be used for reverse supply protection down to –40V.The LTC4231 provides a debounce delay and allows the GATE to be ramped up at an adjustable rate. After startup, the LTC4231's quiescent current drops to 4µA during normal operation with output active. UVL, UVH, OV and GNDSW monitor overvoltage and undervoltage periodically, keeping total quiescent current low. PullingSHDNlow shuts down the LTC4231 and quiescent current drops to 0.3µA.During an overcurrent fault, the LTC4231 actively limits current while running an adjustable timer. The LTC4231-1 remains off after a current fault while the LTC4231-2 automatically reapplies power after a cool-down period.ApplicationsBattery Powered EquipmentSolar Powered SystemsPortable InstrumentsAutomotive Battery ProtectionEnergy Harvesting