SLVSFM1 March 2021 TPS62902
In applications where the TPS62902 is used to power multiple load circuits, the total capacitance on the output can be very large. In order to properly regulate the output voltage, there needs to be an appropriate AC signal level on the VOS pin. Tantalum capacitors have a large enough ESR to keep output voltage ripple sufficiently high on the VOS pin. With low-ESR ceramic capacitors, the output voltage ripple can get very low, so it is not recommended to use a large capacitance directly on the output of the device. If there are several load circuits with their associated input capacitor on a pcb, these loads are typically distributed across the board. This adds enough trace resistance (Rtrace) to keep a large enough AC signal on the VOS pin for proper regulation.
The minimum total trace resistance on the distributed load is 10 mΩ. The total capacitance n x CIN in the use case below was 32 × 47 μF of ceramic X7R capacitors.