A Novel Absorptive Power Delivery Network for Power Noise Mitigation

In this article, for the first time, a power delivery network (PDN) noise absorber is applied to the power system and verified based on a power trace system. Among all the existing absorptive circuits, a low-pass reflectionless circuit is chosen as our PDN noise absorber due to its broadband characteristic. Since the speed of the signal becomes higher and higher nowadays, a millimeter distance of a power trace with the traditional reflective PDN noise suppression devices, such as decoupling capacitors (de-caps), may provide serious standing wave on it and seriously affect the system. The proposed PDN noise absorber, on the other hand, can absorb the PDN noises so that the standing wave on the power trace can be prevented. This makes power trace systems more stable and avoids significant power noises at some locations. A prototype using a PDN noise absorber was fabricated. The power integrity performance of this prototype was compared with two other cases, power trace only and power trace with a de-cap. Compared with the de-cap case at the designed frequency 750 MHz, a PDN noise absorber can reduce 40% maximum voltage ripple. On the other hand, noise coupling between the digital and radio frequency circuits has also been demonstrated and compared for those three different PDNs. It shows a 3.7-dB decrease in gain fluctuation for the PDN with power noise absorber compared with the de-cap case. According to these results, no matter from power integrity or noise coupling suppression viewpoint, PDN noise absorber can be a good candidate to make the power system more stable.