SIM900A Power requirement.

Good morning.

Might be a quick question and I may be asking the obvious but…

I have gotten a SIM900A GSM “modem”. On reading the spec sheet, it says it can occasionally pull 2A while transmitting…

My question is, can I use a supercap (or even a regular cap) rated at 5.5V to give a current reservoir.

OR…do I just get a 3A 5V regulator and be done with it?

The data is only sent every 5 seconds or so…I have no idea if this will work…or does it pull 2A for a significant amount of time?

I have 2 5.5V 4F supers and a box of various normal electrolytic caps (to about 1F).

I can only guess as to the current draw period…but if it were say for 1 second…then:

W(stored in Cap)=C . 0.5 . V(Cap)



C = (I(GSM)V(GSM)) / 0.5 . V(Cap)

C = (2 . 5) / (0.5 . 5.5) = 3.6F

So for a second of operation, i’d need 3.6F to provide the current…