Hello,

I try to power my 8052 system with dc/dc converter MC34063. I used schematics given in datasheet to lower voltage from 12 to 7.5 volts and then low voltage regulator 4940V5 to have 5 volts. I have problems with the ripple. It is in +-100mV, a bit more than in datasheet and obvious reason is switching. Does anybody have experience with 34063? Maybe 8052 will go with it, but attached MT8870 dtmf decoder is sensitive to noise. How can I get rid of high frequency noise? I put 100nf on output of 5 volt regulator. Another idea is to put 100pF across buil-in transistor of MC34063 and across the coil. Do you thik of any better idea? Or better switch back to old LM317?

regards, Damjan