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I would like to use SIM800L for M2M. I have power of 5V 2A for powering uC board and would like to add gsm module. It seems that SIM800L has rather strange voltage input rating: 3.4V - 4.4V. What would be proper way to power it up with this configuration?

One proposal was to use zener diode with VF 1V, is this viable solution?

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  • \$\begingroup\$ What is that strange input rating, 3,4V ~ 4.5V? \$\endgroup\$ – Bence Kaulics Apr 13 '15 at 16:38
  • \$\begingroup\$ Yes 3.4V ~ 4.4V \$\endgroup\$ – user505160 Apr 13 '15 at 16:39
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    \$\begingroup\$ I think that Voltage range is so it will work with a LiPo battery with no regulator as a LiPo is generally in the range of 3.7V - 4.2V 3.7V nominal and 4.2V when charging. \$\endgroup\$ – Matt Dec 1 '15 at 16:46
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You could make a stable 4V from you 5V supply with voltage regulator, like TI's lm2596s. It has an adjustable output version which is capable of driving a max 3A load with excellent line and load regulation, beside providing the adjusted fix voltage (like 4V in your case).

I have used this IC with my GSM module which has similar supply voltage ranges like yours (3.4V - 4.6V, 4 recommended), it works fine.

Though, it requires more components and more space than a single zener diode, I think it is more reliable.

enter image description here

The datasheet has a good Design Component Selection Guide. Also, you can request samples if you have an educational or company e-mail address.

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  • \$\begingroup\$ No samples for educational users these days from TI it seems :( \$\endgroup\$ – berry120 Feb 6 '16 at 23:53
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    \$\begingroup\$ Unfortunetely yes. From 2015 1st of November there are no more samples for educational users, only for companies. Dark day in cheap home proto-typing. \$\endgroup\$ – Bence Kaulics Feb 7 '16 at 12:21

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