Multiplexing an LED matrix is the easiest way to drive a high LED count application. The PWM sources drive the current into the LEDs and are responsible for turning an LED ON or OFF. The sinks are time multiplexed and at any given time only one sink is active. The sinks are cycling through very fast (in a range between 500kHz up to 1MHz) so the multiplexing cannot be seen by the eye. Together this allows each LED to be driven independently. In the example of the AS1115, if the current is set to 40mA an average current of 5mA results for the LED since each LED is only ON for a maximum of 1/8th of the time. This means LEDs used for this system must have a peak current greater than 40mA and a DC current of at least 5mA. The average current of 5mA has to be considered because of the self heating of the LED while the peak current limit of the LED gives the maximum current allowed even if drawn only a short time. For both values customers have to stay within the limits. For the AS1115 this means any LED with a peak current of 48mA and a DC current of at least 6mA will do (taking the maximum values from the datasheet of AS1115).