1) Radiated Emission issue is solved. But failed in Conduction Emission test.
2) The Conduction Emission exceeds standard below 2 MHz (testing range is 150kHz~30MHz). We though it could be caused by the isolated dc-to-dc converter of ADM2587E. to add ferrite bead (high Z at 2MHz) and 10pF, 1uF, 10 uF ceramic capacitor on Visoout, and adjust RC filter on AB lines, but it still failed.
3) uses 2-layer PCB. Customer doesn't want to change to 4-layer PCB for cost reason and they don't have enough time to adjust PCB layout totally.