Switch Mode Step up DC-DC converter

Discussion in 'General Electronics Chat' started by Weiz, May 23, 2012.

  1. Weiz

    Thread Starter New Member

    Dec 10, 2011
    Hi all,

    I have a problem with the choice of parts for my new summer project. I am making a lithium powered USB mobile power supply with an arduino to monitor charge/discharge rates, temperature and simple stuff like switching off when battery is discharged to 2.7V. I will probably etch my own PCB as well.

    However, the main problem i face now is that i cant find a reasonable SMPS that will fulfil my requirements.

    1. Can supply 5V 2A from 2.7V to 4.2V (Using lithium cells to charge my iPad)
    2. Affordable <15USD incl shipping to Singapore
    3. DIP / TO-220 package or something that can be easily soldered
    4. Efficiency above 85% at 2A output

    I have checked out linear, maxim and national semicond... but so far no satisfactory find. Here are some of the chips that i was seriously considering..

    LT1370 - 13USD but I can only find DD Pak package which i am unsure how to solder.

    MAX669 - uMax package which is extremely small to solder and requires quite a number of external components

    MAX1709 - Shipping to Singapore seems extremely expensive.

    Any ideas? Or anyone with spare ICs?

    Thanks in advance.