Analog Devices Inc./Maxim Integrated

The LTC4249 dual electronic circuit breaker (ECB) provides independent overcurrent protection to a pair of loads. Each channel has a precision enable input, current monitor output and ready status output. A single resistor configures the ECB threshold. If either channel detects an overcurrent condition, the corresponding breaker disconnects the input from the load.After a circuit breaker event, the open-drain RDY status output pulls low and the ECB latches off. Toggling the enable input turns the ECB back on after a 1 second cooloff period. An infinite retry option(–2) is also available. The cool-off timer, overtemperature sensor, short-circuit detector and inrush controller prevent operation outside the safe operating area of the circuit breakers.Precision enable inputs, ready outputs and analog current monitor outputs permit voltage sequencing and closed loop bias current control applications. ECB channels may be paralleled as needed. Load isolation and reverse current detection applications are also possible.APPLICATIONS5G mMIMO PA Array ProtectionIndustrial SafetyCondition MonitoringRelay ReplacementLoad Switching

The LTC4251/LTC4251-1/LTC4251-2 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 feed forward path that limits peak current under worst-case catastrophic fault conditions.Programmable undervoltage and overvoltage detectors disconnect the load whenever the input supply exceeds the desired operating range. The 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 LTC4251 UV/OV thresholds are designed to match the standard telecom operating range of –43V to –75V. The LTC4251-1 UV/OV thresholds extend the operating range to encompass –36V to –72V. The LTC4251-2 implements a UV threshold of –43V only.UV/OVLTC4251-43V / -75VLTC4251-1-36V / -72VLTC4251-2-43V UV OnlyLTC4251B-43V / -75VLTC4251B-1-36V / -72VLTC4251B-2-43V UV OnlyApplicationsHot Board InsertionElectronic Circuit Breaker–48V Distributed Power SystemsNegative Power Supply ControlCentral Office SwitchingProgrammable Current Limiting CircuitHigh Availability ServersDisk Arrays

The LTC4251B/LTC4251B-1/LTC4251B-2 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.Programmable undervoltage and overvoltage detectors disconnect the load whenever the input supply exceeds the desired operating range. The 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 LTC4251B UV/OV thresholds are designed to match the standard telecom operating range of –43V to –75V. The LTC4251B-1 UV/OV thresholds extend the operating range to encompass –36V to –72V. The LTC4251B-2 implements a UV threshold of –43V only. The LTC4251B improves the ruggedness of the LTC4251 shunt regulator.UV/OVLTC4251–43V/–75VLTC4251-1–36V/–72VLTC4251-2–43V UV OnlyLTC4251B–43V/–75VLTC4251B-1–36V/–72VLTC4251B-2–43V UV OnlyApplicationsHot Board InsertionElectronic Circuit Breaker–48V Distributed Power SystemsNegative Power Supply ControlCentral Office SwitchingProgrammable Current Limiting CircuitHigh Availability ServersDisk Arrays

The LTC4252 negative voltage Hot Swap™controller allows 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.Adjustable undervoltage and overvoltage detectors disconnect the load whenever the input supply exceeds the desired operating range. The LTC4252’s supply input is shunt regulated, allowing safe operation with very high supply voltages. A multifunction timer delays initial startup and controls the circuit breaker’s response time. The circuit breaker’s response time is accelerated by sensing excessive MOSFET drain voltage, keeping the MOSFET within its safe operating area (SOA). An adjustable softstart circuit controls MOSFET inrush current at start-up.The LTC4252-2 provides automatic retry after a fault. The LTC4252C-1/LTC4252C-2 feature tight ±1% undervoltage/ overvoltage threshold accuracy. The LTC4252 is available in either an 8-pin or 10-pin MSOP.The LTC4252B and LTC4252C improve the ruggedness of the shunt regulator in the LTC4252 and LTC4252A.UV/OV %Latch Off/RetryPackageLTC4252-14.6%Latch offMS-8, MS-10LTC4252-24.8%RetryMS-8, MS-10LTC4252A-11%Latch offMS-10LTC4252A-21%RetryMS-10LTC4252B-14.6%Latch offMS-8, MS-10LTC4252B-24.6%RetryMS-8, MS-10LTC4252C-11%Latch offMS-10LTC4252C-21%RetryMS-10ApplicationsHot Board InsertionElectronic Circuit Breaker–48V Distributed Power SystemsNegative Power Supply ControlCentral Office SwitchingHigh Availability ServersATCA

The LTC4252 negative voltage Hot Swap™controller allows 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.Adjustable undervoltage and overvoltage detectors disconnect the load whenever the input supply exceeds the desired operating range. The LTC4252’s supply input is shunt regulated, allowing safe operation with very high supply voltages. A multifunction timer delays initial startup and controls the circuit breaker’s response time. The circuit breaker’s response time is accelerated by sensing excessive MOSFET drain voltage, keeping the MOSFET within its safe operating area (SOA). An adjustable softstart circuit controls MOSFET inrush current at start-up.The LTC4252-1/LTC4252A-1 latch off after a circuit breaker fault times out. The LTC4252-2/LTC4252A-2 provide automatic retry after a fault. The LTC4252A-1/LTC4252A-2 feature tight ±1% undervoltage/overvoltage threshold accuracy. The LTC4252 is available in either an 8-pin or 10-pin MSOP, while the LTC4252A is available in the 10-pin MSOP.UV/OV %Latch Off/RetryPackageLTC4252-14.6%Latch offMS-8, MS-10LTC4252-24.8%RetryMS-8, MS-10LTC4252A-11%Latch offMS-10LTC4252A-21%RetryMS-10LTC4252B-14.6%Latch offMS-8, MS-10LTC4252B-24.6%RetryMS-8, MS-10LTC4252C-11%Latch offMS-10LTC4252C-21%RetryMS-10ApplicationsHot Board InsertionElectronic Circuit Breaker–48V Distributed Power SystemsNegative Power Supply ControlCentral Office SwitchingHigh Availability ServersATCA

The LTC4253/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 startup 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 sequenced by an adjustable timer and two ENABLE inputs to enable external power modules at start-up or disable them if the circuit breaker trips. The LTC4253A features tight ±1% undervoltage/ overvoltage threshold accuracy. The LTC4253/LTC4253A are available in a 16-pin SSOP.NotesLTC4253LTC4253ARecommendLTC4253Bfor new designsLTC4253A-ADJRecommendLTC4253Bfor new designsLTC4253BApplications-48V Distributed Power SystemsNegative Power Supply ControlCentral Office SwitchingHigh Availability ServersDisk Arrays

The LTC4253B negative voltage Hot Swap™controller allows 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 LTC4253B latches off after a circuit fault.Adjustable undervoltage and overvoltage detectors disconnect the load whenever the input supply exceeds the desired operating range. The LTC4253B’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 softstart circuit controls MOSFET inrush current at start-up.Three power good outputs are sequenced by an adjustable timer and two ENABLE inputs to enable external power modules at start-up or disable them if the circuit breaker trips. The LTC4253B improves the ruggedness of the LTC4253 shunt regulator.NotesLTC4253LTC4253ARecommend LTC4253B for new designsLTC4253A-ADJRecommend LTC4253B for new designsLTC4253BApplications–48V Distributed Power SystemsNegative Power Supply ControlCentral Office SwitchingHigh Availability ServersDisk Arrays

The LTC4253/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 startup 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 sequenced by an adjustable timer and two ENABLE inputs to enable external power modules at start-up or disable them if the circuit breaker trips. The LTC4253A features tight ±1% undervoltage/ overvoltage threshold accuracy. The LTC4253/LTC4253A are available in a 16-pin SSOP.NotesLTC4253LTC4253ARecommendLTC4253Bfor new designsLTC4253A-ADJRecommendLTC4253Bfor new designsLTC4253BApplications-48V Distributed Power SystemsNegative Power Supply ControlCentral Office SwitchingHigh Availability ServersDisk Arrays

The LTC4255 is a quad –48V network power controller with independent relay drivers and I²C compatible interface. Each channel can be turned on and off via software control, while providing short-circuit protection, open-circuit detection, and power good indication. The short-circuit protection includes a current foldback feature to reduce power dissipation in the switch during shorts and start-up.The serial interface allows up to 128 channels to be controlled with only two digital lines. AFAULToutput can be used as an interrupt line to eliminate fault detection by software polling.External switches and current sense resistors allow easy scaling of current and power dissipation levels and provide the maximum protection against voltage and current spikes.The LTC4255 is available in the 28-pin SSOP package.ApplicationsIP Phone SystemsDTE Power Distribution