In this derating graph from the datasheet, the customer can learn which currents one can apply and for how long. This derating is valid at 25°C. There is also a derating graph for ambient temperatures 85°C in the datasheet. The largest current allowed for this LED is 1 A under certain conditions. The D means duty cycle and is the relation between the pulse length to and the total cycle length T. The customer can learn more about how to read these diagrams and find the right maximum specified current for the pulse duration and the duty cycle on ams OSRAM's application support database online.