Dears,
Our product is EV BMS mother board,use ISOW7841 isolate SPI signal.
For ISOW7841,we use 5-V input supply operation,for EMI test,we test RE in ALSE,the result is bad at 238M frequency,is about 60db,more larger than the normal value 38db.we have study the SLLA368A file,so have 3 question:
- If use Y2 CAP,how about the effect on 238M frequency point?Pls promote us a full part number if OK.
- If use Extending the internal reference layers creating a stitching capacitance,as below shot,how about use the two isolate GND layer,GND1 and GND2 to creat the stitching capacitance?not as the SLLA368A said use GND1 and VCC2,it will be OK?
- to calculate Ci,we should consider the two GND1 and GND2's overlapping area,do we need to consider the GND1 layer or the GND2 layer themself area?