SNVS085X July 2000 – December 2017 LM3478
PRODUCTION DATA.
The output capacitor of the SEPIC sees very large ripple currents (similar to the output capacitor of a boost converter). The RMS current through the output capacitor is given using Equation 55.
The ESR and ESL of the output capacitor directly control the output ripple. Use low capacitors with low ESR and ESL at the output for high efficiency and low ripple voltage. Surface mount tantalums, surface mount polymer electrolytic and polymer tantalum, Sanyo-OSCON, or multi-layer ceramic capacitors are recommended at the output for low ripple.