ZHCSHZ8B april 2018 – february 2023 TPS62147 , TPS62148
PRODUCTION DATA
The recommended value for the output capacitor is 22 µF with FSEL = high (fsw = 2.5 MHz) and 2 x 22 µF with FSEL = low (fsw = 1.25 MHz). The architecture of the TPS62147, TPS62148 allows the use of tiny ceramic output capacitors with low equivalent series resistance (ESR). These capacitors provide low output voltage ripple and are recommended. To keep its low resistance up to high frequencies and to get narrow capacitance variation with temperature, it is recommended to use X7R or X5R dielectric. Using a higher value has advantages like smaller voltage ripple and a tighter dc output accuracy in Power Save Mode.
In Power Save Mode, the output voltage ripple depends on the output capacitance, its ESR, ESL and the peak inductor current. Using ceramic capacitors provides small ESR, ESL and low ripple. The output capacitor must be as close as possible to the device.
For large output voltages the dc bias effect of ceramic capacitors is large and the effective capacitance has to be observed.