LT3992Monolithic Dual Tracking 3A Step-Down Switching Regulator | Power Management (PMIC) | 4 | Active | The LT3992 is a dual current mode PWM step-down DC/DC converter with two internal 4.6A switches. Independent input voltage, shutdown, feedback, soft-start, UVLO current limit and comparator pins for each channel simplify complex power supply tracking and sequencing requirements.To optimize efficiency and component size, both converters have a programmable maximum current limit and are synchronized to either a common external clock input, or a resistor settable fixed 250kHz to 2MHz internal oscillator. A frequency divider is provided for channel 1 to further optimize component size. At all frequencies, a 180° phase relationship between channels is maintained, reducing voltage ripple and component size. A clock output is available for synchronizing multiple regulators.Minimum input to output voltage ratios are improved by allowing the switch to stay on through multiple clock cycles only switching off when the boost capacitor needs recharging. Independent channel operation can be programmed using the SHDN pin. Disabling both converters reduces the total quiescent current to <10μA.ApplicationsAutomotive SuppliesDistributed Supply Regulation |
LT399560V, 3A, 2MHz Step-Down Switching Regulator with 2.7μA Quiescent Current | Power Management (PMIC) | 3 | Active | The LT3995 is an adjustable frequency monolithic buck switching regulator that accepts a wide input voltage range up to 60V. Low quiescent current design consumes only 2.7μA of supply current while regulating with no load. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping the output ripple below 15mV in a typical application. The LT3995 can supply up to 3A of load current and has current limit foldback to limit power dissipation during short circuit. A low dropout voltage of 500mV is maintained when the input voltage drops below the programmed output voltage, such as during automotive cold crank.An internally compensated current mode topology is used for fast transient response and good loop stability. A high efficiency 85mΩ switch is included on the die along with a boost Schottky diode and the necessary oscillator, control, and logic circuitry. An accurate 1.02V threshold enable pin can be driven directly from a microcontroller or used as a programmable undervoltage lockout. A capacitor on the SS pin provides a controlled inrush current (soft-start). A power good flag signals when VOUTreaches 91.6% of the programmed output voltage. The LT3995 is available in a small 16-lead MSOP package with exposed pad for low thermal resistance.APPLICATIONSAutomotive Battery RegulationPortable ProductsIndustrial Supplies |
LT3999Low Noise, 1A, 1MHz Push-Pull DC/DC Driver with Duty Cycle Control | PMIC | 3 | Active | The LT3999 is a monolithic, high voltage, high frequency DC/DC transformer driver providing isolated power in a small solution footprint.The LT3999 has two 1A current limited power switches that switch out of phase. The duty cycle is programmable to adjust the output voltage. The switching frequency is programmed up to 1MHz and can be synchronized to an external clock for more accurate placement of switcher harmonics. The input operating range is programmed with the precision undervoltage and overvoltage lockouts. The supply current is reduced to less than 1μA during shutdown. A user-defined RC time constant provides an adjustable soft-start capability by limiting the inrush current at start-up.The LT3999 is available in a 10-lead MSOP and 3mm × 3mm DFN package with exposed pad.ApplicationsLow Noise Isolated SuppliesMedical Instrument and SafetyDistributed PowerMultiple Output SuppliesPositive-to-Negative SuppliesNoise Immunity in Data Acquisition, RS232 and RS485 |
LT4180Virtual Remote Sense Controller | PMIC | 3 | Active | The LT4180 solves the problem of providing tight load regulation over long, highly resistive cables without requiring an additional pair of remote sense wires. This Virtual Remote Sense™device continuously interrogates the line impedance and corrects the power supply output voltage via its feedback loop to maintain a steady voltage at the load regardless of current changes.The LT4180 is a full-featured controller with 5mA optoisolator sink capability, under/overvoltage lockout, soft-start and a ±1% internal voltage reference. The Virtual Remote Sense feature set includes user-programmable dither frequency and optional spread spectrum dither.The LT4180 works with any topology and type of isolated or nonisolated power supply, including DC/DC converters and adjustable linear regulators.The LT4180 is available in a 24-pin, SSOP package.Applications12V High Intensity Lamps28V Industrial SystemsHigh Power (>40 Watts) CAT5 Cable SystemsWiring Drop Cancellation for Notebook Computer Battery ChargingAC and DC AdaptorsWell-Logging and Other Remote InstrumentationSurveillance Equipment |
LT420050A Hot Swap E-Fuse with Guaranteed SOA | Integrated Circuits (ICs) | 1 | Active | The LT4200 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 into a single package for small form-factor applications. The MOSFET safe operating area is production tested and guaranteed for the stresses in hot swap applications.The LT4200 allows 50A of continuous operation at up to 85°C ambient temperature. It provides separate inrush current control and a ±12% accurate 57A current limit with output dependent foldback. The current limit threshold can be adjusted dynamically using the ISET pin. Additional features include a current monitor output for ground referenced current sensing and a MOSFET temperature monitor output. Thermal limit, overvoltage, undervoltage and power good monitoring are also provided.APPLICATIONSHigh Availability ServersSolid State Drives |
LT4220Dual Supply Hot Swap Controller | Hot Swap Controllers | 1 | Active | The LT4220 16-pin dual voltage Hot Swap controller allows a board to be safely inserted and removed from a live backplane. The device operates with any combination of 2.7V to 16.5V and –2.7V to –16.5V supplies. Using two external N-channel pass transistors, the board supply voltages can be ramped up at an adjustable rate. A selectable tracking mode allows dual supply tracking control for ramping the positive and negative supplies together.The LT4220 features foldback current limit and latches off both gates if either supply remains in current limit longer than an adjustable time amount. The IC can be configured for automatic restart after a delay set by the same timer.A power good signal indicates when the output voltages monitored by the two FB comparators are within tolerance, and the gate drive signals are at their full on voltage.The LT4220 is available in a 16-lead narrow SSOP package.ApplicationsLive Board InsertionRAID Systems–5.2V ECL SuppliesIndustrial ControlsSplit Supply Systems |
LT4239High Current Hot Swap Controller with Current Monitor Output | Power Management (PMIC) | 1 | Active | The LT4239 hot swap controller allows a board to be safely inserted and removed from a live backplane. Using external N-channel pass transistors, board supply voltage and inrush current are ramped up at a controlled rate. Dual 12V gate drive supports high current loads by providing a two-stage start-up that first charges the load capacitance followed by enabling a low on-resistance path to the load. The supply output is protected against short-circuit faults with a fast-acting electronic circuit breaker.By placing the sense resistor on the output side and an RC filter at the device’s supply pin, the MOSFET avalanching can suppress the surge voltage when it is abruptly turned off without the additional TVS at the board supply input.The LT4239 features a current monitor that amplifies the voltage across an external sense resistor. It also provides undervoltage protection, and reports fault and power good status for the supply. A boost mode allows the circuit breaker and current limit thresholds to be raised to ride through load surges without generating a fault.APPLICATIONSElectronic Circuit BreakerEnterprise Servers and Data Storage SystemsNetwork Routers and Switches |
LT4250Negative 48V Hot Swap Controller | PMIC | 5 | Active | The LT4250L/LT4250H are 8-pin, negative 48V Hot Swap™controllers that allow a board to be safely inserted and removed from a live backplane. Inrush current is limited to a programmable value by controlling the gate voltage of an external N-channel pass transistor. The pass transistor is turned off if the input voltage is less than the programmable undervoltage threshold or greater than the overvoltage threshold. A programmable current limit protects the system against shorts. After a 500μs timeout the current limit activates the electronic circuit breaker. ThePWRGD(LT4250L) or PWRGD (LT4250H) signal can be used to directly enable a power module. The LT4250L is designed for modules with a low enable input and the LT4250H for modules with a high enable input.The LT4250L/LT4250H are available in 8-pin PDIP and SO packagesApplicationsCentral Office Switching–48V Distributed Power SystemsNegative Power Supply Control |
LT4254Positive High Voltage Hot Swap Controller with Open-Circuit Detect | Power Management (PMIC) | 2 | Active | The LT4254 is a high voltage Hot Swap™controller that allows a board to be safely inserted and removed from a live backplane. An internal driver controls the high side N-channel MOSFET gate for supply voltages ranging from 10.8V to 36V. The part features an open-circuit detect (OPEN) output that indicates abnormally low load current conditions.The LT4254 features an adjustable analog foldback current limit. If the supply remains in current limit for more than a programmable time, the N-channel MOSFET shuts off, the PWRGD output goes low and the LT4254 either automatically restarts after a time-out delay or latches off until the UV pin is cycled low. The RETRY pin sets whether the part will automatically restart after an overcurrent fault or if it will latch off until the UV pin is cycled low.The PWRGD output indicates when the output voltage rises above a programmed level. An external resistor string from VCCprovides programmable undervoltage and overvoltage protection.ApplicationsHot Board InsertionElectronic Circuit Breaker/Power BussingIndustrial High Side Switch/Circuit Breaker24V Industrial/Alarm Systems12V and 24V Distributed Power Systems |
LT4256-1LT4256-2Positive High Voltage Hot Swap Controller with Open-Circuit Detect | Evaluation Boards | 6 | Active | The LT4256-3 is a high voltage Hot Swap™controller that allows a board to be safely inserted and removed from a live backplane. An internal driver controls the high side N-channel MOSFET gate for supply voltages ranging from 10.8V to 80V. The part features an open-circuit detect (OPEN) output that indicates abnormally low load current conditions.The LT4256-3 also features an adjustable analog foldback current limit. If the supply remains in current limit for more than a programmable time, the N-channel MOSFET shuts off, the PWRGD output asserts low and the LT4256-3 either automatically restarts after a time-out delay or latches off until the UV pin is cycled low (depending on the status of the RETRY pin).The PWRGD output indicates when the output voltage rises above a programmed level. An external resistor string from VCCprovides programmable undervoltage and overvoltage protection.The LT4256-3 is available in a 16-lead SSOP package.Retry / Latch OffFeaturesPackageLT4256-1Latch OffUVSO-8LT4256-2RetryUVSO-8LT4256-3Latch Off or RetryUV/OV, Open Circuit DetectSSOP-16ApplicationsHot Board InsertionElectronic Circuit Breaker/Power BussingIndustrial High Side Switch/Circuit Breaker24V/48V Industrial/Alarm SystemsIdeally Suited for 12V, 24V and 48V Distributed Power Systems48V Telecom Systems |
