The recommended value for the output capacitor is 22 µF. The architecture of the TPS629210-Q1 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, TI recommends 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 (see Optimizing the TPS62130/40/50/60 Output Filter Application Note for more information).

In power save mode, the output voltage ripple depends on the following:

• Output capacitance
• ESR
• ESL
• 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, and TI recommends to have the VOS signal and feedback resistors (if used) must be connected to the positive terminal of the output capacitor.

For large output voltages, the DC bias effect of ceramic capacitors is large and the effective capacitance has to be observed.