Anyone? Step down converter from 13.8v to 5v

[LeeCavanagh]

Does anyone have a simple circuit for 13.8v step down converter to 5v ?

Or recommend one

[Bton-FM]

5vreg.png

[LeeCavanagh]

Thanks bton-fm, Appreciated

[Albert H]

Minor changes - connect your 100nF caps right at the legs of the regulator, and use a couple of 4µ7 or 10µ electrolytic capacitors in place of the 10nF.

The 78L05 is only good to 100mA. If you need more current, you'll need a 7805 (good to an amp, but will need a small TO220 heatsink at more than about ½A. If you go for the heavier current device, you'll need the same capacitors to keep RF (in particular) out of the regulator.

[Bton-FM]

Thanks bton-fm, Appreciated

What are you trying to power with this? I presumed it was a PLL?

[Bton-FM]

Minor changes - connect your 100nF caps right at the legs of the regulator, and use a couple of 4µ7 or 10µ electrolytic capacitors in place of the 10nF.

That's how I normally do it with the legs soldered to the middle leg if its a 7805 on a tuner can or as close as possible if it's on a PCB. I guess it depends what it's powering to what the decoupling values are?

[LeeCavanagh]

Thanks bton-fm, Appreciated

What are you trying to power with this? I presumed it was a PLL?

Oh, a tiny pll which only gives out 100mw

[LeeCavanagh]

I did consider using a cigarette lighter to usb charger which i have spare, that give out 5v more than enough amps too

[alfaeire]

I did consider using a cigarette lighter to usb charger which i have spare, that give out 5v more than enough amps too

Most of the time they give out a load of noise too. They can be used, but should be shielded.

Sent from my ONEPLUS A5010 using Tapatalk

[Albert H]

Be REALLY careful with the filtering on the supply if you use the 5V adaptor. They frequently put out ~100kHz ripple, which can appear as spurs on your carrier!

[rigmo]

do not forger electrolyte capacitor

[rigmo]