BQ25600D: Strong 1.5 MHz noise component across broad frequency range.

Due to unavailability of parts, we switched from a BQ24179 to BQ25600 between revisions of our design. The original design with the 24719 showed very low radiated emissions when charging, passing FCC Class B limits with plenty of margin. The new board using BQ2500 shows high levels of 1.5 MHz noise across a wide range of frequencies when charging.  Can you suggest any mitigation actions.  Schematic and layout can be provided.