AVX Advanced Application Capacitors are organized around three distinct functions:

• Application Specific Development Laboratories
• Advanced Manufacturing Facilities
• Quality Control

The output from the switching circuit of a Switcher consists of current on and off. From an elevated DC reference, this current is an AC ripple additive on the DC. In order to smooth this ripple effect, a filter circuit (usually inductive input) is built to allow a storage of energy to take place during the rising ripple portion and to allow a discharge of energy during the falling ripple portion.

The ESR and ESL of the capacitor contribute to the net ripple effect. The output filter capacitor is chosen for ESR, and with previous types of capacitors, multiples were used in an attempt to lower the net ESR. The MLC offers ESRs well below the minimum allowable to lower noise levels, thus eliminating the need for multiple units.

Read more: http://www.avx.com/docs/masterpubs/Advprod.pdf