Relative Jitter Measurement Methodology and Comparison of Clocking Resources Jitter in Artix 7 FPGA

Abstract

Phase jitter is one of the crucial factors in modern digital electronics, determining the reliability of a design. This paper presents a novel approach to designing a jitter comparison system and methodology for FPGA chips using a Tapped Delay Line (TDL)—commonly used to implement a Time-to-Digital Converter (TDC). The design and its revision utilizing latches replacing some of the flip-flops are presented and discussed, with potential further improvements. A minimal temperature influence is verified and presented. The methodology of automated relative jitter measurements is discussed. Multiple different FPGA clock signal path configurations are measured, and the results are presented. The influence of clock routing is identified as critical when MMCM or PLL modules are omitted. It is demonstrated that with careful resource and routing allocation, the clock signal’s jitter performance does not have to be deteriorated by the absence of jitter filtering blocks. The proposed technique was implemented and verified and relative jitter performance was measured in the AMD/Xilinx Artix 7 35T FPGA platform.