Buck regulator

[Makaram]

Hey!
Looking for the right buck regulator for my 12v -> 3v3 circuit.
Do all buck regulators require external components?!
why?

surely theres fully contained ones knocking about if some1 could point me in the right direction,
Thanks

Matt

 

[crutschow]

They all require external components such as inductors and capacitors that are too large to include in the integrated circuit controller.

You can certainly buy completed units on a PC board or contained in a small module such as this. Just google "buck regulator module".

 

[picbits]

Fully contained ones tend to be called "DC to DC converters"

 

[crutschow]

Fully contained ones tend to be called "DC to DC converters"

The term DC-DC converter usually implies isolation between input and output which a standard buck or boost regulator doesn't provide.

If you notice, the reference device I posted was described as a "buck converter module".

 

[ronsimpson]

There are a number of "ICs" that have the inductors and capacitors inside.
SR78/1000 is a TO-220 looking switching regulator. Built to replace a LM7805.

See the data sheet for a LMS7805.

I can't find the part now but I evaluated another TO-220 switching regulator that replaces a LM7805.

There are a number in strange packages.

I don't use them because I can make it. If you volume is low they work well. No engineering effort.

 

[Makaram]

Thanks for the input!
I just searched through the numerous buck regulators on digikey.com and the only one I found that didnt need an external inductor circuit was this https://www.digikey.com/product-detail/en/AN34040A/AN34040A-ND/1835908

Thanks Ron for those devices.

Is there any advantages to fully enclosed ones vs external component ones?

 

[ronsimpson]

The part you showed, DigiKey said it is switching but I don't think it is. Look at the data sheet. It looks like you can switch on/off the supply. I think it is linear.

I also attached a data sheet from Linear. They have many switchers with the inductor inside. This is just one.

"Is there any advantages to fully enclosed ones vs external component ones? " You don't have to think about the parts. Power in/power out, very simple.