Calculation Notes
The differential microstrip is a common technique for routing differential traces. A differential microstrip is constructed with two traces referenced to the same reference plane.
Factors that influence the impedance calculation include:-
- Trace thickness (t)
- Substrate height (h)
- Trace spacing (s)
- Differential impedance (Zd)
- Substrate dielectric (εr)
Z_{d}\approx \frac{174}{\sqrt{\varepsilon_{r}+1.41}}\times\ln\bigg(\frac{5.98h}{(0.8w+t)}\bigg)\times \bigg[1-0.48\;exp\Big(-0.96\frac{s}{h}\Big)\bigg]
References:
- RF Design Guide Systems, Circuits and Equations (ISBN 0-89006-754-6)
- High-Speed Digital Design (ISBN 0-13-395724-1)
- Signal Integrity Issues and Printed Circuit Board Design (ISBN 0-13-335947-6)
- IPC-2141 Controlled Impedance Circuit Boards and High Speed Logic Design
Disclaimer: The information and this tool are provided with no liability of any kind whatsoever, use at your own risk.