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  • Inquire: Call 0086-755-23203480, or reach out via the form below/your sales contact to discuss our design, manufacturing, and assembly capabilities.
  • Quote: Email your PCB files to Sales@pcbsync.com (Preferred for large files) or submit online. We will contact you promptly. Please ensure your email is correct.
Drag & Drop Files, Choose Files to Upload You can upload up to 3 files.

Notes:
For PCB fabrication, we require PCB design file in Gerber RS-274X format (most preferred), *.PCB/DDB (Protel, inform your program version) format or *.BRD (Eagle) format. For PCB assembly, we require PCB design file in above mentioned format, drilling file and BOM. Click to download BOM template To avoid file missing, please include all files into one folder and compress it into .zip or .rar format.

Via Impedance & Stub Calculator | PCBsync
PCB Design Tool

Via Impedance & Stub Calculator

Calculate via barrel impedance and resonant stub frequency for high-speed PCB design optimization

Via Parameters

mm
mm
mm
mm
mm
µm
GHz

Design Tip

For high-speed designs (>5 GHz), consider back-drilling to reduce stub length. A via stub acts as a quarter-wave resonator, causing signal reflections at its resonant frequency.

Calculation Results

Via Barrel Impedance Optimal
-- Ω
Target: 40-60Ω for most applications
Stub Resonant Frequency (λ/4) Check
-- GHz
First null at quarter-wavelength resonance
Via Inductance
-- nH
Total via barrel inductance
Via Capacitance
-- pF
Antipad parasitic capacitance

Frequency Margin Analysis

0 GHz Target: 10 GHz Resonant: -- GHz

Via Cross-Section Diagram

Stub Signal Layer d
Drill Hole
Via Pad
Antipad
Via Stub

Calculation Formulas

Via Impedance (Eric Bogatin Model)

Z₀ = (60/√εr) × ln(1.41 × D₁/D)

Where D₁ = antipad diameter, D = pad diameter, εr = dielectric constant

Stub Resonant Frequency

f_res = c / (4 × Ls × √εr)

Quarter-wave resonance where c = speed of light, Ls = stub length

Via Inductance

L = 5.08 × h × [ln(4h/d) + 1]

Where h = via length (mils), d = drill diameter (mils), L in nH

Via Capacitance

C = 1.41 × εr × T × D / (D₁ - D)

Antipad capacitance where T = board thickness

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Contact Sales & After-Sales Service

Contact & Quotation

  • Inquire: Call 0086-755-23203480, or reach out via the form below/your sales contact to discuss our design, manufacturing, and assembly capabilities.

  • Quote: Email your PCB files to Sales@pcbsync.com (Preferred for large files) or submit online. We will contact you promptly. Please ensure your email is correct.

Drag & Drop Files, Choose Files to Upload You can upload up to 3 files.

Notes:
For PCB fabrication, we require PCB design file in Gerber RS-274X format (most preferred), *.PCB/DDB (Protel, inform your program version) format or *.BRD (Eagle) format. For PCB assembly, we require PCB design file in above mentioned format, drilling file and BOM. Click to download BOM template To avoid file missing, please include all files into one folder and compress it into .zip or .rar format.