| Electronics > Projects, Designs, and Technical Stuff |
| DC-DC Switching regulator, 12v -> 5v and 3.3v |
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| JaspaJami:
Hello Im looking for a switching dc-dc regulator. Input 12vdc, and two outputs: 5v and 3.3v. If it would be about 1000mA for 3.3v and 500mA for 5v that for sure should be enough. I think it can go quite much lower also from that. In i would like it to be as little extra components as possible. Any idea where i should try to find this kind of? At the moment best one is maybe TPS5438x: http://www.ti.com/lit/ds/symlink/tps54386.pdf But that one needs quite a mount of extra components also. |
| t1d:
I did a quick search one Ebay and did not see a dual unit. But, I would think that something being designed for an Arduino, on a bread board, might be dual. Otherwise, use a pre-made converter to drop to 5v and add a small 3v3 circuit, to that... That would just be a 3.3v regulator and a couple of caps... Or two pre-made converters, 5v and 3v3. These buck converters are dirt cheap, on Ebay. |
| JaspaJami:
Trying to find good quality component that i can put on a production PCB. Amounts are not big ones so price is not so huge deal ( i mean if it cost 2€ or 6€, doesn't matter much) |
| mariush:
What's your budget? Check MP2364 : https://www.monolithicpower.com/pub/media/document/MP2364_r1.6.pdf 1.4 Mhz switching frequency so you can use smaller inductors compared to that TPS chip, up to 1.5A per output, around 90% efficient etc If you want really few components there's uModule parts from Linear, like LTM4622 with integrated inductors and everything... you just need a bunch of ceramic caps and resistors to set the output voltages ... but it's potentially pain in the ass BGA package and expensive (7$ in quantity): https://www.digikey.com/product-detail/en/linear-technology-analog-devices/LTM4622IY/LTM4622IY-ND/6181727 Some other food for thought Such a dual output chip as you can see will have around 90% efficiency ... so 3.3v at 1A = 3300mW and 5v at 0.5A = 2500mW , so 5800mW ...at 90% efficiency you're looking at ~ 6500mW power consumption If heat is not an issue, You could go for a cheaper 5v 1.5A+ switching regulator with higher efficiency and then use a LDO for 5v to 3.3v ... the LDO would obviously dissipate 1.7w of heat at 1A but that's doable in a big package... if it's MAX 1000mA , or if you have enough space then it's doable... and especially if it's for some arduino where you'd power from a 12v adapter and not batteries... So for example you could use a 0.5$ AP3513 IC which will still be at least 90% efficient at 2A output and at 5v 1.5A you're looking at 7500mW at 90%, or around 8300mW ... so really less than 2w extra... but the LDO only needs a ceramic capacitor on the output. For example, an AZ1084 is less than 0.5$: https://www.digikey.com/product-detail/en/diodes-incorporated/AZ1084CD-3.3TRG1/AZ1084CD-3.3TRG1DICT-ND/4505193 |
| BFX:
If you need only quick solution try this https://www.ebay.com/itm/LM2596-4-Way-Multiple-Output-Switching-Power-Supply-Module-Board-3-3V-5V-12V-ADJ-/272914677919 otherwise TI part you mentioned is better with little bit of effort to design an build custom solution. |
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