I just designed-in an LM2623. I've designed several supplies using PWM
chips like the SG3525 and UC3845, TL494, MC34063, etc. But this was
the first time I used one of the low-voltage highly-integrated
high-frequency chips. I'm using it to boost two 'AA' batteries (~2v to
3+ volts) to 5v output at about 50mA. It works really well. The design
process was rather arbitrary though. The datasheet basically says to
guess certain component values.. turns out it worked anyway. It
exhibits a decent amount of oscillation at low output current (1-10mA)
but smoothes out at 40+ mA. I tailed the boost converter with an LDO
for my analog circuit, which keeps VDD clean regardless of this noise.

Do you folks have any similar chips that you like?

-
Martin K
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