We found minimum output capacitor information at datasheet P22.
Please let us know maximum output capacitor information.
Customer consider to use SOIC package type.This softstart time is Min:1ms Max:3ms.
So we should care C value below equation to achieve soft start.
I x t=C x V
C=I x t/V
< IoutMAX x 1ms/Vout
If this part has another limitation ,please let us know.
Regards,