# SEPIC converter capicitors calculation

I have got a SEPIC converter design see here: http://www.linear.com/docs/27994 The calculation of the SEPIC converter starts at page 21. For the input capacitance on page 17 they tell you need:

$$\I_{RMS}(C_{IN}) = 0.3 \cdot ∆I_L \$$

This is a current and not a capacitance how can I calculate a capacitance value from this current?

On page 24 they calculate the coupling capacitor current:

$$\I_{RMS}(C_{DC})\$$

but again this is no capacitance. How can I calculate a capacitance from this current?

• Can you paste the schematic as an image in the question? That way if the link breaks the question will still be relevant. – calcium3000 Nov 21 '17 at 18:44

From the datasheet (on page 17, right above your $I_{RMS} = 0.3 \Delta I_L$ equation):