1. What is Bonding Wire Inductance?

Definition: This calculator estimates the inductance of a straight wire conductor above a ground plane, commonly used in bonding wires for electronic circuits.

Purpose: It helps electrical engineers and circuit designers understand and account for the parasitic inductance introduced by bonding wires in high-frequency circuits.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( L \) — Inductance (henrys)
• \( \mu_0 \) — Permeability of free space (4π×10⁻⁷ H/m)
• \( l \) — Length of the wire (meters)
• \( h \) — Height of the wire above ground plane (meters)
• \( r \) — Radius of the wire (meters)

Explanation: The formula approximates the inductance of a straight wire above an infinite ground plane, which is a common configuration in electronic packaging.

3. Importance of Bonding Wire Inductance

Details: In high-frequency circuits, even small inductances can significantly affect circuit performance, causing signal integrity issues, impedance mismatches, and unwanted resonances.

4. Using the Calculator

Tips: Enter the wire length, height above ground plane, and wire radius. All values must be > 0. For best accuracy, use consistent units (meters).

5. Frequently Asked Questions (FAQ)

Q1: What is μ₀ (mu-zero)?
A: It's the permeability of free space, a fundamental physical constant equal to 4π×10⁻⁷ H/m.

Q2: How does wire radius affect inductance?
A: Thinner wires (smaller radius) have higher inductance because the current is more concentrated.

Q3: What's a typical bonding wire inductance range?
A: For 1mm long gold bonding wires, inductance typically ranges from 1-10 nH.

Q4: Does this formula account for wire shape?
A: No, this is for straight wires. Curved or looped wires would require different calculations.

Q5: When is bonding wire inductance most problematic?
A: At high frequencies (especially RF and microwave), where even small inductances can create significant reactance.