kicad/pcb_calculator/attenuators/pi_formula.md

Pi Attenuator

a is attenuation in dB
Z_in is desired input impedance in Ω
Z_out is desired output impedance in Ω

L = 10^a/20
A = (L+1) / (L−1)

R2 = (L−1) / 2·√(Z_in · Z_out / L)
R1 = 1 / (A/Z_in − 1/R2)
R3 = 1 / (A/Z_out − 1/R2)