Change in ESR of the Output Capacitor
The effect of capacitor’s ESR on the reliability and MTTF
of the converter is discussed in this section. The ESR of the
output capacitor was varied from 0.1 to 0.2 Ω in steps of 0.02 Ω.
RDS(ON) and C were set to 34 mΩ and 10 μF, respectively.
Similar to RDS(ON) variation, the failure rate of the converter
increases with any increase in the ESR. However, the failure
rate of the converter is less sensitive to the ESR compared with
RDS(ON). The failure rate and MTTF of the converter versus
ESR is shown in Fig. 8. The MTTF of the converter is reduced
by approximately 140 h for the variation in the ESR ranging
from 0.1 to 0.2 Ω.