Dual Stripline Impedance Calculator

Provide values for four of the five parameters h, c, t, w, Z₀ and the relative permittivity of the dielectric. Click the button corresponding to the unknown parameter to calculate its value ( w/(h-t) <0.35; t/h <0.25; 1 < ε_r <15 ).

Select the units for all dimensions: mm mils

(Thickness) :

mm mils

(Separation) :

mm mils

(Trace thickness) :

mm mils

(Trace width) :

mm mils

ε_r (Relative permittivity) :

(Characteristic impedance):

ohms

C₀ (Capacitance):

pF/cm pF/inch

T_pd (Propagation delay time):

psec/cm psec/inch

Notes:

• The formulas used here are taken from the Design Guide for Electronic Packaging Utilizing High-Speed Techniques (4th Working Draft, IPC-2251, February 2001).
  
• Range of valid parameters specified in the Design Guide: w/(h-t) < 0.35; t/h <0.25; 1 < ε_r < 15
• Accuracy: For typical PCB parameters (ε_r = 4, h = 15 mil, c = 10 mil and t = 1.37 mil), the deviation of the calculated results from results obtained using a 2D numerical field solver, is listed below:
  

  Z₀

  w/(h-t) < 0.04

  more than 30%

  0.04 < w/(h-t) < 0.08

  within 5%

  0.08 < w/h < 0.35

  within 1%

  C₀

  w/(h-t) < 0.04

  more than 80%

  0.04 < w/(h-t) < 0.08

  within 5%

  0.08 < w/h < 0.27

  within 10%

  0.27 < w/h < 0.35

  within 12%