[sdiy] get 5V from 12V - DC-DC converter or 7805?

[Chris McDowell]

my bet would be that a switching regulator will likely not trash your supply rails if you have an electrolytic and ceramic cap on the input, and an inductor and cap suitably sized for your current draw. this isn't super complicated, but might be more worrying than you want to do / need to do.

an LDO like the LM1117 works great for what you want. you will likely waste about 200mW, which in this application probably doesn't matter. it would be a questionable choice for something with batteries, but this aint that.

I've used cheap chinese dc-dc in these kinds of situations, it works and did not completely trash the rails. popular euro manufacturers use the LM1117 and folks seem to be happy! 

if you are worried about using too much current, the arduino nano might be the wrong choice in the first place, but the simplicity trade off might be worth the high-ish current draw. I'm not immediately aware of arduino compatible tiny boards with super low draw. 

cheers,
Chris

> On Dec 27, 2020, at 6:41 PM, MTG <grant at musictechnologiesgroup.com> wrote:
> 
> What about an LDO if the current draw isn't much?  I used these a long time ago:
> 
> LP2950ACZ-5.0
> 
> https://www.ti.com/store/ti/en/p/product/?p=LP2950ACZ-5.0/NOPB
> 
> GB
> 
> 
>> On 12/27/2020 2:18 PM, Tony Allgood wrote:
>> The OKI-78SR-5/1.5-W36-C is pin compatible with a traditional 7805 linear regulator. The disadvantage is that it is more expensive and creates a small amount of high frequency noise that is both radiated and into the power rails. The amount of noise depends on the current draw from the +5V line, with greater currents creating more noise.
>> 
>> If the current draw is less than 100mA, I'd be tempted to use a 78M05.
>> 
>> Tony
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