kicad/pcb_calculator/attenuators/pi_formula.md

PI Attenuator

Zin desired input impedance in Ω
Zout desired output impedance
Zin = Zout

• a attenuation in dB
• L = 10^a/20 (the loss)
• A = (L + 1) / (L - 1)
  
  
• R2 = (L- 1) / 2 * √ ( (Zin * Zout) / L)
• R1 = 1 / (A / Zin - 1 / R2)
• R3 = 1 / (A / Zout - 1 / R2)