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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?

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    \$\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

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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.

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  • \$\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

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