Help with LM2675 data sheet

Discussion in 'General Electronics Chat' started by spinnaker, Dec 29, 2012.

  1. spinnaker

    Thread Starter AAC Fanatic!

    Oct 29, 2009
    I am having with the coil selection chart for the LM2675. The LM2675 is a simple switcher power convertor from TI.

    My input voltage is going to be <14V and my current supplied <.2A

    I need to know what coil to use. Really how to select it form this chart:


    It is real obvious where you choose the max input voltage and load current but when you look to where the two intersect, I am not seeing a suggested coil. Would my coil be L11?
  2. crutschow


    Mar 14, 2008
    Yes, L11 should be the correct coil per the chart for your requirements. Any combination of input voltage and output current within the polygon outline labeled L11 would work with that coil. Just note that at low current levels below 0.2A, the regulator may go into the discontinuous mode (inductor current drops to zero between switching pulses), which may cause a small increase in output noise and ripple.
  3. spinnaker

    Thread Starter AAC Fanatic!

    Oct 29, 2009
    Thanks for clearing that up. So I was reading it correctly.

    The polygon you mentioned is the one formed by the darkest of the black lines correct?

    I was going to add additional output LC filtering. Maybe a 1uh coil and 100ufd cap?
    It is going to run a pic and LCD.

    What other specs in the coil should I look for? Low resistance as possible?