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BQ24170 1.6MHZ Switching Harmonic Spikes

Other Parts Discussed in Thread: BQ24170

Hello,

I am currently using the BQ24170 as the PMIC in a design. I am charging a 2 cell series Lipo pack at 8.4V 1A. The input voltage is 12V 1.5A from an adapter.

My issue is that when the adapter is plugged in and I'm charging the battery and the PMIC is in constant current mode, I get clear 1.6MHz spikes across a broad spectrum. When I look at the emissions on my Spec An, i can clearly see these 1.6MHz spread spikes and they go awway when I pull the adapter (and conversely my bench supply so I'm fairly certain it's not from the power source). This spiking is currently prohibiting me from passing EMC. Has anyone seen this before and/or have any thoughts as to how I can attack this issue? My layout for this circuit is very similar to the BQ24170 EVM (15V) layout.

Thanks!

Dave