• LT3757 High Voltage flyback MOSFET choice

    On page 30 of the LT3757 boost/flyback/sepic/inverting controller; there's an application for a 300V flyback design.

    The switching MOSFET selected for this design is a VISHAY SILICONIX Si7850DP which has a max drain-source voltage of 60V.

    When simulating…

  • LT3757 output collapse on load

    I'm using the LT3757 in both SEPIC and CUK converters in vehicle mounted equipment to provide symmetrical output rails at ±21V. Vin is nominally 12V. Load current is up to about ±150mA. We have built many hundreds of these devices with no issues. I have…

  • LT3757 flyback converter output voltage and current

    Hi All,

    I am using LT3757 flyback converter application and run the simulation in LTspice.

    I want to use LT3757 convert 12V input to 180V. The SCH is same as the example in datasheet, which shows below, and i changed the  16.2K resistor to 31.4K Ohm.


  • LT3757 used with low voltage supply

    I have an application using an LT3757 powered from 3.3V with a switching FET power from a separate higher voltage supply.  The application circuits for the device show a direct connection between the gate drive of the LT3757 and the gate of the MOSFET…

  • LT3757 circuit simulation for +/-12V

    Referring to the application note Boost, Flyback, SEPIC and Inverting Controller, I have tried to stimulate the output voltage using LTSPICE for the +/-12V circuit (Page 32).


    The transformer is 1,2…

  • LT3757 dual output sepic convertor Design


    Could you please share application note for dual output sepic converter design for LT3757? 

    My requirements are:

    Input 10V to 24V

    Output: +26V 0.25A & +26V 0.25A. 

    The datasheet shows design for single output sepic (mentions only L1 and L2) not…

  • LT3757 for 2KV/5mA boost converter


    I have used LT3757 to design a boost converter to generate 2000V/5mA(10Watt)  power from 6V to 14V DC supply.

    Circuit works fine in simulation of LTSPICE but are there any practical considerations to be taken care?

    Any recommendations for transformer…

  • Question LT3757 Flyback Bipolar Power supply

    Hello Currently I am looking in to building a AC to DC High Voltage Bipolar Power supply with the LT3757 Flyback Regulator I would like to attain a maximum current of 100mA, at 500V+- is this possible with this topology

    if so, is there a spreadsheet…

  • LT3757 boost converter control loop instable

    Dear Analog Team,

    i built the simple boost converter which is shown at page 1 of the LT3757 data sheet. In general, it does work, it converts the power. But the output voltage is unstable, there is a sawtooth/triangle on it. The converter runs unwanted…

  • LT3757 SEPIC Configuration Low Input Voltage AC waveforms

    Hello, I have a design using the LT3757 as a SEPIC converter for a power supply board.  The LT3757 takes an input voltage that can vary from 10.5V up to ~17V, and converts to 12V @ 6A.  When I draw full load and decrease the input voltage below ~11-12V…