zcwaa22:
does this mean that it can output 16 x 120mA all at once?
Yes....with certain caveats.
When you light up a LED you have a supply voltage, eg. 5V. The LED will use part of that (eg. 3.6V for a green LED) and the chip has to dissipate the leftover part as heat.
The problem is the 'leftover'. The bigger the difference between the supply voltage and the LED voltage, the more leftover there is. eg. The chip will get far hotter running the 3.6V LED from a 12V supply than from a 5V supply.
So...you can run all 16 LEDs at 120mA, IF the total power the chip has to dissipate at any time is less than about 1500mW.
This is less than 100mW per LED. At 120mA your supply voltage has to be less than (100/120)=0.83V away away from the LED voltage. You can use external resistors to drop the voltage to within that range.