ams OSRAM offers two versions of IR chips in most of their packages. The standard version usually has a voltage of 1.6 V, which is the energy needed by the electricity to overcome the p/n junction responsible for the light emission. One can think of it as a waterfall making noise, as an example. The Nanostack version would be to place a second waterfall after the first one; the noise doubles. It basically means that two junctions are in series within the chip. Therefore, the customer needs to double the voltage to operate these LEDs as well. On the other side, it will become almost double the light. To be exact, somewhere around 185 and 190%, depending on the device. Since one gets almost the value of two LEDs but only needs one package, the price per light power is actually lower. Just for itself, the chip without Nanostack is more efficient, but depending on the circuit and driver design one might end up with a more efficient system at higher voltages using the Nanostack. Operating the Nanostack version at high currents will result in a system that needs a smaller amount of LEDs to accomplish the same illumination task, therefore reducing the amount of LEDs, secondary optics and required real state on the PCB. The advantages of the standard device are its lower cost, its higher wall-plug-efficacy, and its higher maximum DC current ratings.