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Diode Selection Guide

RTCA DO-160, Environmental Conditions and Test Procedures for Airborne Equipment, is a widely used criterion for verifying the capability of equipment to withstand the effects of lightning induced electrical transients.

In Section 22 of this standard, entitled Lightning Induced Transient Susceptibility, the test methods and procedures for performing pin injection and cable bundle testing on aircraft equipment are defined. In order to verify the capability of an electronic system to withstand the effect of lightning induced transients, test procedures define the lightning induced transient by two characteristics.

  1. The transient waveform which shows how quickly the transient is induced and how long it lasts. This is sometimes referred to as the pulse width and is measured in seconds. The pulse width is related to the level of damaging energy contained within the transient, i.e. the longer the pulse, the more damage it will cause. The three most commonly referenced pin injection lightning waveforms from RTCA/DO-160E, Section 22, are shown in the figures below.
  2. The test level which defines the magnitude of the pulse. This is related to the anticipated level of exposure of the electronic system, i.e. if a system is tucked away in a safe environment, e.g. inside a metal enclosure with the interconnecting wiring being well shielded, the test level will be low. However, if the system is highly exposed to the electromagnetic environment, the test level will be high. The test level is described in terms of the open circuit voltage (Voc) and the short circuit current (Isc).

In the table below for waveforms 3, 4, and 5A, we show the recommended diode clamping voltage (Vc) and power rating (Ppp) at each test level for these waveforms.

Diode Clamping Voltage (Vc) Selection for Lighting Strike Waveform Threats

RTCA/DO-160    LEVEL 1 100V/4A LEVEL 2 250V/10A LEVEL 3 600V/24A LEVEL 4 1600V/60A LEVEL 5A 3200V/128A Recommended TVS (Ppp) @10/1000μs
Waveform 3 1MHz Damped Sinusoidal Wave (Ref. Fig. 22-4 from DO-160E) Vc ≤ 97 V Vc ≤ 243 V Vc ≤ 275 V Vc ≤ 87 V Vc ≤ 32.2 V 500 Watts
Vc ≤ 97 V Vc ≤ 243 V Vc ≤ 275 V Vc ≤ 87 V Vc ≤ 35.8 V 600 Watts
All All All Vc ≤ 243 V Vc ≤ 96.8 V 1,500 Watts
All All All Vc ≤ 275 V Vc ≤ 209 V 3,000 Watts
All All All All Vc ≤ 275 V 5,000 Watts

Peak Chart

RTCA/DO-160    LEVEL 1 50V/10A LEVEL 2 125V/25A LEVEL 3 300V/60A LEVEL 4 750V/150A LEVEL 5A 1600V/320A Recommended TVS (Ppp) @10/1000μs
Waveform 4 Double Exponential 6.4 X 69 μsec (Ref. Fig. 22-5 from DO-160E) All All Vc ≤ 31.9 V Vc ≤ 11.3 V NONE 500 Watts
All All Vc ≤ 38.2 V Vc ≤ 13.6 V NONE 600 Watts
All All All Vc ≤ 35.0 V Vc ≤ 16.0 V 1,500 Watts
All All All Vc ≤ 74.0 V Vc ≤ 29.2 V 3,000 Watts
All All All Vc ≤ 134 V Vc ≤ 35.5 V 5,000 Watts
All All All All Vc ≤ 114 V 15,000 Watts
All All All All Vc ≤ 146 V 30,000 Watts
All All All All All 200,000 Watts    @ 10/40us

Voltage Waveform


RTCA/DO-160    LEVEL 1 50V/50A LEVEL 2 125V/125A LEVEL 3 300V/300A LEVEL 4 750V/750A LEVEL 5A 1600V/1600A Recommended TVS (Ppp) @10/1000μs
Waveform 5A Double Exponential 40 X 120 μsec (Ref. Fig. 22-6 from DO-160E) All Vc ≤ 10 V     Vc ≥ 114.9 V NONE NONE NONE 500 Watts
All Vc ≤ 12.4 V   Vc ≥ 112.6 V NONE NONE NONE 600 Watts
All Vc ≤ 42.2 V   Vc ≥ 82.8 V Vc ≤ 12.1 V None NONE 1,500 Watts
All All Vc ≤ 25.5 V Vc ≤ 9.4 V NONE 3,000 Watts
All All Vc ≤ 45.8 V Vc ≤ 15.9 V NONE 5,000 Watts
All All All Vc ≤ 49.9 V NONE 15,000 Watts
All All All Vc ≤ 77.4 V NONE 30,000 Watts
All All All Vc ≤ 231 V NONE 200,000 Watts    @ 10/40us

Current Voltage Waveform