TRANSIENT SUPPRESSION FOR LIGHTNING AND EMP APPLICATIONS & LIGHTNING INDUCED TRANSIENT SUSCEPTIBILITY
In addition to designing for control of steady-state electromagnetic interference (EMI/EMC), modern avionics engineers must also design for immunity to lightning-induced transient susceptibility. These requirements vary by equipment type and environmental area and are defined by a variety of military and commercial specifications including RTCA/DO-160 Section 22. The nature of the transient event ranges from very low-level disturbances, requiring little or no protection, to high frequency and high energy events that can be disruptive or destructive to the avionics equipment. In general, practices which are good for control of EMI/EMC will also serve to mitigate the effects of lightning-induced transients, but further measures must often be taken to ensure proper system operation and survivability. One of the more effective methods available is the inclusion of circuit protective devices in the circuit at the input of the LRU.
While conventional EMI filter connectors have been shown to be effective in providing protection against low energy transients, they offer little protection from high voltage/high energy transients that may result from lightning, load switching, electrostatic discharge (ESD) or electromagnetic pulse (EMP).
TRANSIENT PROTECTION CONNECTORS
ACC has the capability to provide transient voltage suppression (TVS) diodes inside of virtually any connector package regardless of arrangement or contact density. This approach allows design engineers to exceed the requirements outlined in DO-160 Section 22 while retaining valuable space inside the box being protected and saving circuit board space by eliminating bulky surface mount or axially leaded TVS diodes.
COMBINING THE TRANSIENT SUPPRESSION DEVICE INTO THE CONNECTOR PROVIDES SEVERAL ADVANTAGES:
- Reduces system design time
- Allows for retrofit of existing equipment requiring lightning or EMP hardening
- Transient protection can be combined with EMI filtering
- Mixture of electrical requirements including; power, voltage & capacitance
- Protection is located at the system interface
- Electrical components are protected by the shell housing, reducing environmental & mechanical damage
- Mainly for transient suppression
- Repairability is better on connector than on board
- Factory replaceable
- If failure on PCB, harder to replace and potentially FOD concerns
- Ideal for retrofits or transients after the PCB is designed