MC34063A Optional Filter help.

[RayMonster]

Hi!

I have managed to build a step up converter 10v to 20v  150ma output
It works fine. 

However the output ripple exceeded the designed spec of 100mv.
From the data sheet, the values for capacitor & inductor was fixed without any calculations.
May i know is there a way to calculate the values for this optional filter?

Thanks!

[ali6x944]

The output filter is basically an LC low pass filter...
Google lc low pass filter calculator and u can free ur self from all the annoying calculations, also can u post ur calculations for the MC34063 converter please just so I can check with u...

[RayMonster]

Hi just to check if im doing this right. This is the output i have, i ripple is about 40mv ignoring those random spikes.
To filter off those spikes, does adding a low pass helps resolve this?

Thanks Lots.

[ali6x944]

Can u show me the circuit and how u are connecting the probes to it ?