An alternate power distribution scheme with superior noise suppression characteristics than EBG

Abstract

This work presents an efficient power delivery network design for mitigating the coupling of power supply noise in mixed-signal electronics using power transmission lines. Digital circuitry operating at high data rates generates supply noise that can interfere with sensitive RF circuitry. Currently used methods, such as split planes and ferrite beads, have limited isolation bandwidth and can pose difficulties for signal integrity. Electromagnetic bandgap (EBG) structures have also been shown to exhibit excellent noise isolation. In this paper, a set of parallel digital buffers and a low noise amplifier are powered by a power transmission line instead of a voltage plane. An embedded bandstop filter in the power transmission line significantly reduces the amount of coupled noise between the digital and RF supply voltage pins. Test vehicles using this proposed method, as well as using an EBG structure were fabricated and tested. The proposed method shows a 16dB decrease in coupled power as compared to the EBG. Incorporating an EBG in the power delivery network gives rise to impedance peaks that cause larger power supply noise at the supply pin of the buffers. Consequently, the proposed method also demonstrates significant improvement in signal and power integrity by reducing the power supply noise at the source, as shown in the conducted lab measurements.