A Simple Technique for Power Distribution With Better Characteristics Than Electromagnetic Bandgap Structures

TLDR: In this paper, a power transmission line (PTL) instead of a voltage plane is used to mitigate the coupling of power supply noise in mixed-signal electronics, and an embedded bandstop filter in the PTL significantly reduces the amount of coupled noise between the digital and RF supply voltage pins.

Abstract: This paper presents a simple power delivery design for mitigating the coupling of power supply noise in mixed-signal electronics. Digital circuitry operating at high data rates generates supply noise that can interfere with sensitive RF components. 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 been shown to exhibit excellent noise isolation characteristics. In this paper, a set of parallel digital buffers and a low-noise amplifier are powered by a power transmission line (PTL) instead of a voltage plane. An embedded bandstop filter in the PTL significantly reduces the amount of coupled noise between the digital and RF supply voltage pins. In addition, a source terminating the PTL provides good noise isolation with even lower supply noise. The proposed methods are easy to design and implement and use much less space than an equivalent EBG structure. Test vehicles using these proposed methods, as well as using an EBG structure, were fabricated and tested with regard to power supply noise, jitter, and noise isolation. The proposed methods show up to 13-dB decrease in coupled power compared with the EBG. In addition, the measured supply noise is decreased by 75% and the total jitter in the transmitted eye diagram is improved by 23% using the proposed method.