Even though I'm focusing most of my new development effort on the next gen #LiFePO4wered/Pi+, that doesn't mean the LiFePO4wered/Pi shouldn't get any love!

One thing that I've started to notice now I've sold over 750 of these things is that the part that gives me the most trouble is the MIC2876 boost converter.  It's the only part that gives any trouble really.  The tiny little DFN package seems to not always be mounted correctly on the boards I get from the CM, so I need to rework some of them and that's a pain.  Worse, I've even had some field returns where units that were working fine before shipping, would not work when they arrived at the customer, and it's always this part that's been the problem on the returns I've analysed.

So I've been looking for a more robust replacement and I think I've found a good candidate to try: the Richtek RT4812.  It has a nice small leaded package, so assembly problems should go away, and with power MOSFETs that have 1/2 to 1/4 the RdsON as those in the MIC2876, it also should heat up less under heavy load, possibly extending the load current range.

So I've made a prototype layout to evaluate this change:

The RT4812 runs at a lower switching frequency than the MIC2876 and specifies a larger output capacitance, plus it doesn't have a fixed output voltage version, so between the extra capacitors and resistive divider the layout has become even more dense.  But it all fits and that's what counts. :)  The design has been sent to OSH Park, I can't wait to see how it performs!