3,3 V switcher

Prefs are clear, but most difficult is “price”. I try find 3,3 V dc-dc-converter or switcher circuit, but must be cheap.

  • Input: Input voltage max 35 VDC, minimum is not relevant (10 V or under)
  • Output: 3,3V, 100 mA
  • All ideas ok, but linear regulator is not good idea,heat sink…
  • Target price 0,5 usd. Incl: 1xinput EMC-coil, 2xinput capacitor, circuit, schottky, resistors, output capacitors. (0,5 usd in 1000 piece)
  • Eg. dc-dc-converter CUI VXO-7803-500, Mornsun K7803MT-500R4‎ are very good examples, BUT too expensive…


Hi Please see link for all the stocking options in a 3.3v out. I do not think you are going to find anything less expensive than the VXO-7803-500 you list. Glenda

Power Supplies - Board Mount | DC DC Converters | DigiKey

Hi Elkesan,

For example using MP4410 one can build an economical switcher, but
0.5USD is probably still hard to reach.

What is the estimated volume? BOM & NRE costs go down as the volume gets higher, but there are other costs to consider too (assembly, test, etc).
Say, if your target volume is 1000 units, then the batch cost can be only 500USD. With that money it may be hard to get even the assembly done.


1000 maybe target volume.

Also I check 1E6 different solution. Of course, discrete components (just as any switcher circuit). But, also I check “7803-switchers” as this CUI-VXO etc. (Also Ebay, aliexpress, octopart etc etc…) Maybe it is good idea use “7803-switcher”: it is not as cheap as on-board, but more flexible.

It is, I desing my main board use “7803 switcher”. Original input signal is 10 VDC/VAC up to 24 VAC/VDC. Output of the regulator must be 3,3V/100 mA. Maybe I make main board as “standard way”, rectifier, input capacitor electrolytic, eg. 100 uH coil, 10 uF capacitor. After “7803” any 10-20 uF X5R…X7R. After this it is possible install “7803” to three hole.

Three hole:

  • Any “7803 switcher”, CUI or any other. (Also it is possible order any set “ebay-aliexpress-7803”…)
  • “Home made” “7803 switcher”, it is, if found cheap solution it is possible make “7803-ownboard”

Maybe this way is not most cheapest. But, this is very flexible. Maybe it is clever idea use “7803 switcher”… reason of flexibility…


You could also consider this:
Costing only 1USD. Cannot imagine how such is possible though.