TPS40210-Q1: about Cout selection for Fly-back use

Hi Team

I am using TPS40210-Q1 as Fly-Back; Vin = 18V ~ 36V, Vout = 28V, Iout = 3.6A,

I want to know how to calculate the proper Cout.

the below equation is correct to use ?

Cout >=              Iout x Nps x Vout

              --------------------------------------------------------

               ∆Voutripple x Fsw x (Vinmin + Nps x Vout)

[ Nps : primary to secondary transformer turn ratio,

   ∆Voutripple : peak to peak ripple voltage at Vout,

  Vinmin : Min vlotage at Vin ]