AN165 Datasheet - Crystal

AN165 EMI REDUCTION TECHNIQUES

Common-mode radiation is the result of undesired voltage drops due to voltage differentials in the I/O ground system. The CS4297A clock transitions result in a rush of current that may induce the digital ground plane to "bounce". When external speaker or microphone cables are connected to the audio .

www.DataSheet4U.com AN165 Application Note CS4297A/CS4299 EMI REDUCTION TECHNIQUES 1. INTRODUCTION The CS4297A and CS4299 AC ’97 audio codecs are based on a new and faster fabrication process, and certain precautions in the analog I/O circuitry may be required to prevent 49.1 MHz commonmode radiation. Note that 49.1 MHz is 2 times the CS4297A internal clock frequency of 24.576 MHz. 3. EMI SHUNTING CIRCUIT The key to reducing common-mode emissions is to add decoupling (called shunting) at the .

AN165_Crystal.pdf