signal integrity

Microstrip Impedance From Zo

Inverse microstrip calculator — computes the trace width needed to achieve a target characteristic impedance Zo, along with propagation delay, inductance, capacitance, and resistance per unit length.

Inputs

Target Impedance(Ω)

Target characteristic impedance in ohms (typically 50Ω or 75Ω)

Trace Thickness(mm)

Thickness of the PCB trace in millimetres

Dielectric Thickness(mm)

Thickness of the dielectric substrate in millimetres

Relative Dielectric Constant

Relative permittivity of the dielectric — FR4: ~4.5, Rogers 4003: ~3.55

Results

⚠Target impedance must be greater than zero

Trace Width—mmRequired trace width in millimetres to achieve target impedance

Propagation Delay—ps/cmPropagation delay per centimetre in picoseconds

Inductance—nH/cmDistributed inductance per centimetre in nanohenries

Capacitance—pF/cmDistributed capacitance per centimetre in picofarads

Resistance—mΩ/cmDC resistance per centimetre in milliohms