MC33063A: MC33063ADR question about CT terminal capacitor?

Hi Bob,

This capacitor defines the max. on time of the internal NPN. It can't decide the switching frequency, as the device is not fix frequency operation.

if this pin is short, there is risk that the IC got damaged.

Dear Jasper Li,

Thank you very much for your answer.
May I ask a add question about your answer?

(About question)
So your answer that 'It can't decide the switching frequency, as the device is not fix frequency operation.'

(Datasheet)
By datasheet Pin Function description,
Timing capacitor is attach a timing capacitor to change the switching frequency.

(Question)
Does CT capacitor use change switching frequency?
Or
Does not CT capacitor use change switching frequency?

Best regard.
Bob Lee.

Hi Bob,

the CT can only define the maximum switching frequency from the operating principle. the device may operates at a frequency lower than frequency setting by CT. the actual frequency depends on other external components and the loading.

Dear Jasper Li,

Thank you very much for your answer.
May I ask a add question about your answer?

(About question)
So your answer that 'the CT can only define the maximum switching frequency from the operating principle. '

(Question)
Could you teach define the maximum switching frequency calculation?

Best regard.
Bob Lee.

Hi Bob,

the frequency is 1/(ton+toff). you can find the ton and toff from the page 6 in the datasheet.