Study on single-ended vias in high speed PCB
Author(s): WANG Hong-fei, CHEN Bei
Pages: 10-14
Year: 2014 Issue: 7
Journal: Printed Circuit Information
Keyword: Vias; Impedance Control; High-Speed PCB; Insertion Loss;
Abstract: In high-speed digital board designs, parasite capacity and inductance on vias have to be considered carefully. Vias can lead to impedance discontinuities resulting in signal relfections and hence deterioration of signal integrity. This paper carried out a comprehensive study of the impacts of various via design parameters on impedance discontinuities of vias by vector network analyzer. The design parameters under study were via diameter, via height, pad diameter and anti-pad diameter. By adding ground vias near the signal vias to provide return current path for signal in vias, impedance of vias can be accurately controlled, and insertion loss of vias can be greatly decreased. Furthermore, impact of excess via-hole stub on vias’ impedance and insertion loss were studied. This paper allows high-speed digital designers to have a more in-depth assessment of via holes design and optimization.
Pages: 10-14
Year: 2014 Issue: 7
Journal: Printed Circuit Information
Keyword: Vias; Impedance Control; High-Speed PCB; Insertion Loss;
Abstract: In high-speed digital board designs, parasite capacity and inductance on vias have to be considered carefully. Vias can lead to impedance discontinuities resulting in signal relfections and hence deterioration of signal integrity. This paper carried out a comprehensive study of the impacts of various via design parameters on impedance discontinuities of vias by vector network analyzer. The design parameters under study were via diameter, via height, pad diameter and anti-pad diameter. By adding ground vias near the signal vias to provide return current path for signal in vias, impedance of vias can be accurately controlled, and insertion loss of vias can be greatly decreased. Furthermore, impact of excess via-hole stub on vias’ impedance and insertion loss were studied. This paper allows high-speed digital designers to have a more in-depth assessment of via holes design and optimization.
Related Articles