EMI Issues in Pseudo-Differential Signaling for SDRAM Interface

H-field EMI measurements have been performed for the single-ended, the differential, and the pseudo-differential signaling on a 11” FR4 microstrip line. The pseudo-differential signaling reduces EMI by more than 10 ㏈ compared to the single-ended signaling if the delay mismatch is lower than 5% of a period for a 3 ㎓ clock signal. Empirical H-field equations for both differential and single-ended signaling showed fair agreements with measurements.