Figure 11-1 shows the recommended placement and routing of device bypass capacitors. Below guidelines must be followed to achieve low emissions design:

1. High frequency bypass capacitors 10 nF must be placed close to V_DD and V_ISOOUT pins, less than 1 mm distance away from device pins. This is very essential for optimised radiated emissions performance. Ensure that these capacitors are 0402 size so that they offer least inductance (ESL).
2. Bulk capacitors of atleast 10 µF must be placed on power converter input (V_DD) and output (V_ISOOUT) supply pins.
3. Traces on V_DD and GND1 must be symmetric till bypass capacitors. Similarly traces on V_ISOOUT and GND2 must be symmetric.
4. Place two 0402 size Ferrite beads (Part number: BLM15EX331SN1) on power supply pins, one between V_ISOOUT and V_ISOIN and the other between GND2 (11) and GISOIN(15), as shown in example PCB layout, so that any high frequency noise from power converter output sees a high impedance before it goes to other components on PCB.
5. Do not have any metal traces or ground pour within 4 mm of power converter output terminals V_ISOOUT (pin12) and GND2 (pin11). MODE pin is also in V_ISOOUT domain and should be shorted to either pin 11 or pin 12 for output voltage selection.
6. Common mode choke or ferrite beads on bus terminals (Y/Z/A/B) can minimise any high frequency noise that can couple of RS-485 bus cable which can act as antenna and amplify that noise. This will improve Radiated emissions performance on a system level.
7. Following the layout guidelines of EVM as much as possible is highly recommended for a low radiated emissions design. EVM Link is available in Related Documentation.