Board Level Shield Design Features & Assembly
Design features for attenuation and noise reduction
‘Quiet’ Venting – As devices carry more power, they generate more heat and require ever more cooling. The addition of a shielding may raise the operating temperature of the device past the critical limit.
Perforations have been made in shields for many years, the maximum permissible dimension being a function of the device frequency and the level of attenuation desired. Contact MAJR for optimization.
Quiet venting can increase the open area of a shield for optimum cooling by perforating a pattern of very small holes, effectively a mesh, into both the walls and tops of shields. This process also reduces the ‘maximum linear dimension’ to improve attenuation performance and does not add significantly to the part cost of the shield. To perforate the walls of a ‘drawn’ can requires multi-stage tooling which can be costly.
Quiet venting also has the additional benefit of enabling some vision systems to ‘look’ inside the can to check component existence and correct placement.