What is current forward (if) of an IR LED
Forward current (If) of a diode is the maximum safe current you can continuously pass through the device without causing it damage. The circuit is expected to limit the current through the device to this amount if there will be no pauses in the current (100% duty cycle). The parameter exists for IR LEDs, visible LEDs, and normal rectifiers, but the exact amount varies for each family as well as each specific model.