How to make 3.3V from 5V

[SevenZero]

Most of the modules such as GPS, GPRS modules require +3.3 VDC ±0.3 VDC. There are two methods I can suggest here. One is to use the LM317 Linear regulator and the other is to use a AMS1117-3.3 linear regulator. Let's see how we can do that.

Making 3.3V from 5.0V using a LM317 Linear Regulator

1.GIF (3.2 KiB) Viewed 6171 times

Making 3.3V from 5.0V using a AMS1117-3.3 Linear Regulator

2.JPG (24.78 KiB) Viewed 6171 times

If you are from Sri Lanka, you can buy these parts fromTRONIC.LK.

[SemiconductorCat]

I've noted that ceramic caps on both sides in figure 2 but they absent in design 1 with LM317.
Any idea why is that?

Is this equation is correct regarding here?

Code: Select all

?(ESR² + Xc²) = acceptable ripple voltage/ ripple current

and in the design 1, I have another question , why we have to use 25v on c1? Due to defense against transients?
or we just use it to fiffle (x5) the lifetime of the capacitor? Since I can't read your mind I have these questions.

any why not ripple filter was invoked in design 1 there ?

[SevenZero]

Caps are for ripple rejection. yes. For more info, refer datasheets of both regulators.

[SukhdeepMankoo]

You can make 3.3V from 5V using LM3940. it best to choose,because it does not require any external circuit to make 3.3V,Just give input and get output.