I want to power SIM800L which requires around 4v and 2amps(at peak only). If I attach DC buck converter to Arduino Uno 3.3V output, and power SIM800L, is it safe?

  • 1
    \$\begingroup\$ A buck converter can't convert 3.3V to 4V. \$\endgroup\$
    – Justme
    Commented Jun 9, 2020 at 5:03
  • \$\begingroup\$ No it doesn't. It specifically says input voltage must be higher than output voltage. \$\endgroup\$
    – Justme
    Commented Jun 9, 2020 at 5:18
  • \$\begingroup\$ @Justme Got it Sir! Thanks. I didn't read that carefully. \$\endgroup\$ Commented Jun 9, 2020 at 5:20

1 Answer 1


Buck converters step down voltage.

Boost converters step up voltage.

The 3.3V of an arduino is limited by the arduinos regulator and is unlikely to support 4v * 2A or 8W stepped up, which would likely be 3.3V 2.4 Amps plus the efficiency penalty of the regulator (say 20% so 3.3V * 3A). It will burn out. Those on board arduino regulators are only good up to 1 amp in best conditions.

  • \$\begingroup\$ Ok I got the difference between buck and boost converters. \$\endgroup\$ Commented Jun 9, 2020 at 5:20
  • \$\begingroup\$ If I use 20V 2 Amp power supply, get two buck convertors, Power one arduino and other powers sim800l? Will it be OK? \$\endgroup\$ Commented Jun 9, 2020 at 5:22
  • \$\begingroup\$ Yeah that should \$\endgroup\$
    – Passerby
    Commented Jun 9, 2020 at 5:53
  • \$\begingroup\$ @ Passerby In this case, don't the Power supply unit eliminate the need for capacitors? \$\endgroup\$ Commented Jun 9, 2020 at 6:03
  • \$\begingroup\$ Notreally. The buck converters will need some and you probably need some for the sim radio as 2 amps at peak is needed very fast and the caps help smooth out the power draw. \$\endgroup\$
    – Passerby
    Commented Jun 9, 2020 at 6:05

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.