ZHCSBB1D July 2013 – March 2018 UCC28740
The output capacitance value is often determined by the transient-response requirement from the no-load condition. For example, in typical low-power USB-charger applications, there is a requirement to maintain a minimum transient VO of 4.1 V with a load-step ITRAN from 0 mA to 500 mA. Yet new higher-performance applications require smaller transient voltage droop VOΔ with ITRAN of much greater amplitude (such as from no-load to full-load), which drives the need for high-speed opto-coupled voltage feedback.
Additional considerations for the selection of appropriate output capacitors include ripple-current, ESR, and ESL ratings necessary to meet reliability and ripple-voltage requirements. Detailed design criteria for these considerations are beyond the scope of this datasheet.