We use LMR62014 in a design to convert input voltages of 3.3 to 5V to an output voltage of 6.5V @ 120mA max.
with very good results. Switcher is stable over all line, load and temperature conditions. The design is well
produced in quantities of >3000 per year.
Since approx. one month we encoutered problems with the switcher behaviour in the following manner:
switching frequency rises from 1.6MHz to 2.3MHz
heavy undershoot (1.2V) when internal mosfets switches
approx. 1.2times more input power dissipation
lot of more EMI
We could fix up the problem. Obviously there are two kinds of chip production lots which differ from each other,
GOOD: chip marking top = SH1B, chip marking bottom = 48K, SOT23 thickness = 1.03mm, rounded case
BAD: chip marking top = SH1B, chip marking bottom = 3192, SOT23 thickness = 0.85mm, sharp edged case
Has anyone similar experience with LMR62014?
@TI-engineers: can you confirm chip markings?
