I've built a buck smps around the LM2734X. This is meant to power servos, running off a 12V battery source. Scoping the +5V line using smaller servos, I see a stable voltage, with a peak to peak of 50-100mV. When I plug in a bigger servo (it's a B1226, and I've been unable to find a legitimate datasheet for it), I see the following on startup:
I'm using an inductor that's got a 1.2A saturation current. I've been seeing input currents of about 200mA on startup (@12.6V), but once saw it spike up to 400mA momentarily. That got me thinking that the DMM may not be fast enough to show this power on spike, and that I may actually be approaching the limit of the SMPS and the inductor.
Does this look like the inductor saturating? I'm particularly confused by how even the spikes are - they seem to be right at 20ms increments.