Problem with relay current requirement and how to increase current in DC circuit?
Read what it says in the data sheet: -



It says the 5V coil version has a resistance of 70 ohms and this implies a nominal current of 71mA (they say 73mA but I used my calculator).

They also say that they will all activate at 75% of 5V and this usually means 75% of current so, to guarantee it operates it needs 54mA. However that could be just while the relay pull-in the contact because they hint that the relay (if you are lucky) may stay pulled-in when the voltage/current drops to 5% - most won't of course but an educated guess would be that once the relay has activated you can probably relax the current down to maybe 30% but don't bank on it.

So, by the looks of it you need to use a transistor to turn the relay on. Below is an idea for a 12V relay but using 5V and a 5V coil will be OK: -



Any NPN BJT would virtually fit the bill. PS don't forget the diode across the relay coil - when the transistor open circuits, there can be a substantial kick-back voltage from the magnetic energy stored in the relay coil.