Military and Aerospace PCB Design
At PCB design, a mil/aero circuit board may be rated at 5 amperes. However, during pre PCB pre-layout simulation, it’s best to add a 30 to 40 percent buffer as added insurance. Thus, operational amperage on which the circuit board can operate is increased to 6.5 – 7.0 amps, just in case the board is exposed to extraordinarily hot, rugged, and/or hostile environments where there is a chance for an unexpected power surge thereby increasing the operational amperage.
If a mil/aero board is designed at 6 layers during the layout stage, 2 additional layers can provide extra ground planes to ensure clear signals with no crosstalk or noise. The more solid the ground planes are, the better the traces are separated and noise reduced. Reliability increases by an estimated 15% – 20% by making this adjustment at the layout stage.
Extra grounding and shielding on critical traces are also important to boost the reliability of a mil/aero PCB by about 10%-15%. Particular traces demand extra grounding and shielding to protect digital signals from noisy analog ICs which are nearby.