• LT3999 Simulation


    I am running a LTSpice simulation using in-built LT3999 macro model test fixture available. The test fixture is designed for a 12V input, 12V output, 0.4A load which seems to be working well.

    However, when the load is changed to 1kohm and Rdc set…

  • RE: LT3999 switch node voltage


    It is recommended to use a snubber in this case. Too much of negative voltage might affect the IC ground and its internal logic. 



  • RE: LT3999, negative transient on UVLO input

    I do not think that will damage the part. However, this is not tested and not guaranteed. 

  • RE: LT3999 transformer

    Hi Grant, 

    These parts are not order-able from those major distribution websites like digikey or mouser. However, they are order-able and sample-able from Coilcraft and Wurth. Please contact Daniel Blair <dblair@coilcraft.com> from Coilcraft to get more…

  • Problem with LT3999


    Iam using the LT3999 in series with a push Pull Trafo from würth (750315371) to generate 12VDC isolated.

    After a powerup, the first few seconds all works fine but then the output voltage begins to oscillate and as a result, the LT3999 is getting…

  • LT3999 adjacent Tranformer


    i want to use LT3999 to build 12V and 0.8A power supply. according to datasheet i have to use a  COOPER BUSSMANN CTX02-19062  to adjust LT3999. but there isnt any transformer in this name around the internet. does anyone has information?

  • Simulation of LT3999


    I am simulating the LT3999 with : Vin = 13V, Rt = 35k, Rdc = open, Txfr=200uH n=1:1.  The problem is that the output voltage won't ramp to its final value unless I add an output inductor after the output diodes.  Why is it required?


  • LT3999 POWER dissipation calculation

    In the LT3999 datasheet below equations given.

    1) The quiescent current and switch drive power

    PVIN = VIN
    ISW •DC

    where ISW is the average switch current.
    2) The conducting power dissipation of the switches during
    on state…

  • LT3999 programmed duty cycle

    Hi there!

    I have been built a push-pull converter with LT3999 and Coilcraft's PA6384-ALD. I would like to have cca. 10.5V output (nothing special just two diodes, 2uF caps on the secondary side with 10k load) while having 8-34V on the input. Maybe i am…

  • About the primary inductance of the LT3999

    In the link: www.analog.com/.../high-frequency-push-pull-dc-dc-converter.html, equation 14 and equation 15. They both have a factor "Ts/4". I wonder how the figure '4' come from? Thanks.