ESD Clamping Voltage

V_clamp = V_br + I_esd × R_dyn

Quick answer

This calculator solves V_clamp = V_breakdown + I_esd × R_dynamic for Clamping Voltage. With Breakdown Voltage 26.4 V, ESD Current 2 A, Dynamic Resistance 0.47 kΩ, the result is 0.9664 kV. It solves in 4 directions, so you can enter the values you have and get the one you need.

Calculator

Clamping Voltage (V)
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Formula

V_clamp = V_breakdown + I_esd × R_dynamic

Description

ESD protection devices like TVS diodes and varistors clamp transient voltages by conducting the surge current once their breakdown voltage is exceeded. The actual voltage seen by the protected circuit during an ESD event is higher than the breakdown voltage because of the device dynamic resistance. Lower dynamic resistance means better clamping and less voltage overshoot. The clamping voltage must remain below the absolute maximum rating of the protected IC to prevent damage.

Variables

  • V_clamp — Peak voltage during ESD event (V)
  • V_br — Breakdown or trigger voltage of the protection device (V)
  • I_esd — Peak ESD current (A)
  • R_dyn — Dynamic resistance of the protection device (Ω)

Practical Notes

IEC 61000-4-2 contact discharge at ±8 kV produces a peak current of 30 A with a rise time of less than 1 ns. TVS diodes typically have R_dyn of 0.3-2Ω, while varistors may have 1-10Ω. For USB, HDMI, and other high-speed interfaces, select ESD protection with low capacitance (< 1 pF) to avoid signal degradation.

Symbols and units

Symbol Meaning Default unit Accepted units
V_clamp Clamping Voltage V pV, nV, µV, mV, V, kV
V_br Breakdown Voltage V pV, nV, µV, mV, V, kV
I_esd ESD Current A pA, nA, µA, mA, A, kA
R_dyn Dynamic Resistance Ω mΩ, Ω, kΩ, MΩ

Step by step

  1. 1. What you know: Breakdown Voltage 26.4 V, ESD Current 2 A, Dynamic Resistance 0.47 kΩ
  2. 2. The relation: V_clamp = V_breakdown + I_esd × R_dynamic
  3. 3. Substitute: V_br = 26.4 V, I_esd = 2 A, R_dyn = 0.47 kΩ
  4. 4. Result: Clamping Voltage = 0.9664 kV

Related quantities from the same inputs

  • P = V × I = 52.8 W

Worked examples

Minimum range

Given: Breakdown Voltage 0.726 V, ESD Current 2 mA, Dynamic Resistance 1 Ω

Result: Clamping Voltage = 0.728 V

Low range

Given: Breakdown Voltage 7.26 V, ESD Current 20 mA, Dynamic Resistance 10 Ω

Result: Clamping Voltage = 7.46 V

Typical

Given: Breakdown Voltage 26.4 V, ESD Current 2 A, Dynamic Resistance 0.47 kΩ

Result: Clamping Voltage = 0.9664 kV

High range

Given: Breakdown Voltage 0.506 kV, ESD Current 100 A, Dynamic Resistance 4.7 kΩ

Result: Clamping Voltage = 470.5 kV

Maximum range

Given: Breakdown Voltage 5.06 kV, ESD Current 1 kA, Dynamic Resistance 47 kΩ

Result: Clamping Voltage = 47010 kV

Solving for each variable

Solve for Clamping Voltage

Breakdown Voltage 0.726 V, ESD Current 2 mA, Dynamic Resistance 1 Ω → 0.728 V

Solve for Breakdown Voltage

Clamping Voltage 0.33 V, ESD Current 2 mA, Dynamic Resistance 1 Ω → 0.328 V

Solve for ESD Current

Clamping Voltage 0.33 V, Breakdown Voltage 0.726 V, Dynamic Resistance 1 Ω → -0.396 A

Solve for Dynamic Resistance

Clamping Voltage 3.3 V, Breakdown Voltage 1.55 V, ESD Current 20 mA → 87.5 Ω

How Clamping Voltage changes with Breakdown Voltage

Breakdown Voltage (input) Clamping Voltage (result)
2.64 V 0.9426 kV
6.6 V 0.9466 kV
13.2 V 0.9532 kV
19.8 V 0.9598 kV
26.4 V 0.9664 kV
39.6 V 0.9796 kV
52.8 V 0.9928 kV
105.6 V 1.046 kV
0.1848 kV 1.125 kV
0.264 kV 1.204 kV

The same result in other units

Unit Value
mV 966400
V 966.4
kV 0.9664

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Frequently asked questions

How do you calculate ESD Clamping Voltage?

Use V_clamp = V_breakdown + I_esd × R_dynamic. With Breakdown Voltage 26.4 V, ESD Current 2 A, Dynamic Resistance 0.47 kΩ, Clamping Voltage works out to 0.9664 kV.

What is the formula for ESD Clamping Voltage?

The formula is V_clamp = V_breakdown + I_esd × R_dynamic. ESD protection devices like TVS diodes and varistors clamp transient voltages by conducting the surge current once their breakdown voltage is exceeded.

How do you find Breakdown Voltage when you know the other values?

Rearrange for Breakdown Voltage: with Clamping Voltage 0.33 V, ESD Current 2 mA, Dynamic Resistance 1 Ω, Breakdown Voltage is 0.328 V.

How do you find ESD Current when you know the other values?

Rearrange for ESD Current: with Clamping Voltage 0.33 V, Breakdown Voltage 0.726 V, Dynamic Resistance 1 Ω, ESD Current is -0.396 A.

What units does ESD Clamping Voltage use?

Clamping Voltage is shown in mV, V, kV. Values are held in SI base units internally, so you can mix prefixes without converting by hand.

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