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:-

• Single ended impedance (Z_o)
• Trace spacing (s)
• Substrate height (h)

Z_{d}\approx 2\times Z_{o}\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.