LTM4622A
Recommended for New Designs
The LTM4622A is a complete dual 2A step-down switching mode μModule® (micromodule) regulator in a tiny ultrathin 6.25mm × 6.25mm × 1.82mm LGA and 2...
Datasheet
LTM4622A on Analog.com
Hello,
I'm implementing the LTM4622A with a combined 7V output and 2.2 MHz switching frequency.
To further reduce some expected high-frequency switching noise, what is the recommended approach for attenuation to < 1 mVpp, while also preserving the crossover stability of the supply?
Thank you.
Hi, I don't use the LTM4622A, but with switching converters a good layout is paramount. Otherwise your whole ground plane gets noisy. This then counteracts all further filtering.
If your load is pretty constant, best thing is a LC-filter. With the inductor, keep an eye on the self resonant frequency. Maybe you'll need a series damping resistor also.
Have a look on EMIFIL from murata or similar from other manufacturers
With additional ceramic capacitors, you have to consider that their capacitance is heavily voltage dependant. Choose one in bigger casing (eg. 1210). Or even better, parallel some smaller value ones.
Give them many vias in close proximity.
The 100µF will only be effective for lower frequencies. Polymer or special high frequency tantalum capacitors work best.
Thank you for your response, Alexxx.
Agreed on careful layout and power plane management.
Also note, I'm using the two outputs in parallel for multiphase operation (and reduced ripple), so the internal LCs are expected to be in parallel. I calculate 1.1uH of first-stage inductance.
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