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60V, 4A Synchronous Step-Down Regulator with Adjustable Rail-to-Rail Output & Wire Drop Compensation

Jan 18 2016 - MILPITAS, CA
  • The LTC3649 is a high efficiency, 60V, 4A synchronous buck regulator that incorporates a constant frequency, current mode architecture and programmable output current and output voltage, which are set with a single external resistor. The LTC3649 operates from an input voltage range of 3.1V to 60V and provides an adjustable rail-to-rail output voltage range from 0V to 0.5V below VIN, while delivering up to 4A of continuous output current. Its wide input and output voltage range is ideal for a wide range of test, measurement and industrial applications. The LTC3649’s unique design includes an accurate internally generated 50µA current source on the ISET pin, enabling it to deliver outputs as low as 0V with the use of a single external programming resistor. Furthermore, the LTC3649 offers ±0.8% output voltage accuracy and programmable output current with ±4% accuracy without a sense resistor. Its switching frequency is user programmable from 300kHz to 3MHz, enabling the use of tiny, low cost capacitors and inductors. Combined with a 28-lead 4mm × 5mm QFN or thermally enhanced TSSOP package, the LTC3649 offers a very compact solution footprint.

    The LTC3649 uses internal power switches with RDS(ON) of only 100mΩ and 50mΩ to deliver efficiencies as high as 95%. Burst Mode® operation offers high efficiency at light loads, requiring only 440µA of quiescent current. For noise sensitive applications, the LTC3649 can run in forced continuous mode, offering very low output ripple. Additional features include ±4% accurate output current monitoring, a power good voltage monitor, programmable wire drop compensation, external synchronization capability and thermal protection.

    The LTC3649EUFD is available in a 4mm × 5mm QFN-28, the LTC3649EFE is offered in a 28-lead, thermally enhanced TSSOP package. Industrial grade versions, the LTC3649IUFD and LTC3649IFE, are guaranteed to operate over the –40°C to 125°C operating junction temperature range. Pricing starts at $5.65 each in 1,000-piece quantities. All versions are available from stock. For more information, visit

    Summary of Features: LTC3649

    • Wide VIN Range: 3.1V to 60V
    • Wide VOUT Range: 0V to (VIN - 0.5V)
    • Single Resistor VOUT Programming
    • Integrated 110mΩ Top N-Channel/50mΩ Bottom N-Channel MOSFETs
    • 95% Efficiency with 12VIN and 5VOUT
    • Active IQ: 440µA, Shutdown IQ: 15µA
    • Accurate Current Monitoring (±4%) without Sense Resistor
    • Accurate Resistor Programmable Frequency (300kHz to 3MHz) with ±50% Frequency Sync Range
    • Accurate Programmable Output Current Limit
    • Input Voltage Regulation for MPPT Applications
    • ±0.8% Output Voltage Accuracy
    • Peak Current Mode Operation
    • Programmable Wire Drop Compensation
    • Burst Mode® Operation, Forced Continuous Mode
    • Internal Compensation & Programmable Soft-Start
    • Overtemperature Protection
    • Available in Thermally Enhanced 28-Lead 4mm × 5mm QFN & TSSOP Packages

    60V, 4A Monolithic Synchronous Step-Down Regulator Offers 95% Efficiency & Rail-to-Rail Outputs

    LTC3649 PR Image

    The USA list pricing shown is for budgetary use only. International prices may differ due to local duties, taxes, fees and exchange rates.

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