MC33063A Questions

Tim Ta

Other Parts Discussed in Thread: MC33063A

Hello there,

Below are my questions regarding the application for the MC33063A device;

From data sheet of MC33063A Figure 11, Page 15: When plug in values of R1 = 1.2K and R2 = 3.8K the Vo = 5.2V instead of 5V.

If Vin fluctuate between 24-40 VDC will this affect the 5V regulation? The reason I ask this question because I try to use the filter output from the secondary output of 24VAC transformer. The output could vary between 18-30VAC. this roughly equal to 24-40VDC after filter.

Thanks,

Tim Ta

over 9 years ago

0 Anston Lobo over 9 years ago

TI__Genius 16025 points

I don't think this is a device we can help with. Let me redirect your post to the right forum.

Thanks,
Anston

0 JohnTucker over 9 years ago in reply to Anston Lobo

TI__Guru**** 191445 points

A search for "NC33063A" does not return any hits. Are you sure about that part number?

0 JohnTucker over 9 years ago in reply to JohnTucker

TI__Guru**** 191445 points

Looks like you meant "MC33063A". I'm going to edit the tile of your post.

0 Michael J Schultis over 9 years ago in reply to JohnTucker

TI__Mastermind 24975 points

Hello Tim,

Welcome to the forum. Yes, even if the input voltage fluctuates, then we expect the output voltage to be set to the desired voltage. I expect that there may be some ripple on the output during transitions in the input voltage, but ultimately it should settle to the set voltage.

Note that the minimum inductor value is based on Vin(min). Also there is a good application note that talks more about applications of the MC33063 device: http://www.ti.com/lit/an/slva252b/slva252b.pdf

You are correct about the voltage calculation. Nonetheless, the formula is still correct, but I can have this updated in the next datasheet revision.

Best,
Michael

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MC33063A Questions