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EMC problem with ADSP BF524

Question asked by gudjon on Sep 9, 2013
Latest reply on Sep 11, 2013 by gudjon


   I have just finished a product using ADSP BF524 that works nicely except that it fails emission tests with peaks at 480, 720 and 960MHz. Using sniffer probes I am pretty sure this stems from the high speed USB interface. The USB lines are 80mm long with 90Ohm differential impedance, no sharp corners nor stubs. The only rule that is not followed is to let the PCB factory check the impedance. As far as I know the Blackfin processor contains all terminating resistors needed.

   Do you have any suggestions on how, if possible, to fix this problem?