Recommendations on a +5v/2A (through hole) voltage regulator?

Hey gang-

I'm looking for a replacement voltage regulator.

Needs to be a strict/stable +5v with I'm hoping to have at least 2A as well.. (and hopefully affordable! I see some that are like several dollars each!)

What makes these jump up in price when searching? Being LDO? The current requirement?

The less supporting components the better! ..but a couple caps is fine! :slight_smile:

I usually just fall back on my LM7805's.... but I need to have more current available.

The initial goal was to use a +7.4v li-ion battery pack with the project.... (but would be nice to have a choice of a +6v pack instead)

But if there is a low drop out variant that meets the specs above... that would be great! (would be able to allow +6v packs to work as well...and leave it up to the end user!)

If a SMD version can only be found.... (I'd prefer it to have HUGE spacing between pins!.. or just through hole!)

I'm not clear if an LDO regulator is what I want? Or a 'switching' regulator?

I found these:

or this one
5v / 2A

Is that drop out correct? 0.1v @ 1Amp?

Linear regulators get a lot more expensive above 1A or so (note - that's peak / headline spec 1A - in practice, without additional cooling or an input voltage very close to the output voltage, a "1A" regulator can't supply 1A for long); at that point, dumping the heat starts to become really problematic and the wasted power becomes more concerning as well. Most designers - particularly in this day and age - would opt for a more efficient buck converter instead of a linear regulator.

Linear regs are only well suited for low current applications.

If you are using 7.4v li-ion battery pack you can ignore low drop out, this kind of batteries kept constant voltage to about 90% discharge, so use LM138; 5A, i dont know the price.

Holy crap!@!!

Almost $50 bucks??


  • This is going to be used in a pcb I’m making… so an additional board itself wont work unfortunately…

RE: LM138

*I have never used an adjustable voltage regulator before… how do you normall set the output to be stable? some resistors & caps?

The LM309 looks nice… except it takes a min of +7.1v for INPUT! (BOOOO!)

I was hoping for something fixed, and easy to use like the LM7805… (but with at least 2A output)…


I’m trying to keep the power source/battery pack as close to 5v as possible… hence the +7.4v li-ion pack choice… but also wanted to let the user have more easily available options like 4 x AA = +6v pack…

The current is for a bunch of Neopixel/Dotstar LEDS… (which I believe there will be 48 in total (2 x 24 led rings)…
They will not be full on (white)… so 36mA each is a high projection… but using that… 36mA x 48 leds = 1.7+Amps…

I also do not believe they will be on for a long period of time… mostly short ‘bursts’ of being ‘on’…

So when you say ‘linear’ regs are only good for low current… I should be looking for… switching types is that it?

I understand that LDO = low drop out, as in you dont lose too much voltage from your source over the regulator…

But I’m not exactly clear what a ‘switching’ regulator does? (do they have LDO switching regulators? or is not even a ‘thing’?)

1 AUD =0.771309USD

Holy crap!@!!

Almost $50 bucks??

Holy crap!@!!
1.61 AUD =1.24203USD

Ahh... I thought you were referring to this one from that link:

(therer were many listed.... and that matched the title)

but THESE are the ones you meant??? (correct?) (matched the 1.61 price you commented about)

Switching regulators use a mosfet and inductor to increase or decrease voltage more efficiently by switching the power into the inductor on and off.

Look up buck converter on Wikipedia. For increasing the voltage, it's called a boost converter.

I would buy a cheap buck converter module on eBay, and put pins in the right place to mount it on your board (designing a pcb with your own switching converter on it is hard - they are very layout sensitive) - you can get assembled modules for less than it would cost to get the parts via the magic of China + ebay.

What are you trying to power with it? Is it something that's sensitive to a little ripple? If not, a buck convertor would run cooler and extend battery life.

As mentioned.. it will power Neopixels... roughly 48 of them.

Only the red die and partial green die are lit.. so maybe 38mA (which is a high estimate) per led tops.

I see mention of buck/booster converters...etc.. but I'm not clear, as I do NOT want to boost my voltage?

I want a steady/stable +5v out put.... with 2A (or more) available...

In a perfect world.. I'd like a simple approach like the LM7805 (regulator and some caps).. but that meets the specs above (2A)

I'm not comfortable with DrAzzy's suggestion,.. only because of my (lack of) experience in this area..... not because I dont believe or trust him! LOL :slight_smile: (quite the contrary to be fair)

I always get a little 'weirded' out when I 'blindly follow things without a true (or even a little) understanding myself.

ted recommended something like this:

Price is sure right! LOL..

but I have never even used a regulator like this before.. (and to be honest I havent even looked up the data sheet or anything on it....yet!!!)

  • How big are those things?
  • Do they need caps..etc?
  • Is it adjustable? or fixed? (I prefer the later,.. again because of my experience level on this topic/hardware)

about 3/4ths of an inch in diameter, maybe 1 inch. Adjustable, 2 resistors and input and output caps required. See the datasheet. You definitely need a heatsink if pulling 2A from one - with 2x LiPo's, 4.2v each (full charge) you'd be dumping 3.4v as heat, meaning ~7 watts!

A buck converter under similar operating conditions would use less current as the input voltage got higher, so with 2A output, 1.2~1.5A input depending on charge state of batteries, and might waste ~1W as heat; battery life would be 30-50% longer
Search ebay for "dc dc step down" and you will find tons of modules, many for $1~3 each. The cheap ones have no short circuit protection or anything; I've let the smoke out of a few by shorting the output. But who cares, they cost less than a cup of coffee.

Buck converter is DC-DC converter where input is higher than output voltage and ground is common. Boost is the same, only where input voltage is lower than output voltage. You need a buck converter; I mentioned boost because they are closely related and you sounded like you wanted to research how they worked.

apologies for poorly written reply, I had a nicer one typed out, then accidentally closed the tab when I tried to switch to it.

diameter 20mm, very old.