Maximum operating flux density, BM (Gauss).The cycle skipping mode of operation used in LinkSwitch-XT can generate audio frequency components in the transformer. To limit this audible noise generation, the transformer should be designed such that the peak core flux density is below 1500 Gauss (150 mT). Following this guideline, and using the standard transformer production technique of dip varnishing, practically eliminates audible noise. Vacuum impregnation of the transformer should not be used due to the high primary capacitance and increased losses that result. Higher flux densities are possible, however careful evaluation of the audible noise performance should be made using production transformer samples before approving the design. Audible noise may also be created by ceramic capacitors that use dielectrics such as Z5U, when used in clamp circuits may also generate audio noise. If this is the case, try replacing them with a capacitor having a different dielectric, for example a film type. Flux densities above 3000 Gauss (300 mT) are not recommended.