T6311A

The T6311A low-dropout bias supply for white LEDs is a high-performance alternative to the simple ballast resistors used in conventional white LED designs. The T6311A uses a single resistor to set the bias current for four LEDs, which are matched to 0.3%. The T6311A consumes only 40uA of supply current when enabled and 0.05uA when disabled.

The T6311A advantages over ballast resistors include significantly better LED to LED bias matching, much lower bias variation with supply voltage variation, significantly lower dropout voltage, and in some applications, significantly improved efficiency. The T6311A requires a 200mV dropout at a 9mA load on each output to match the LED brightness. The T6311A is available in SOP-8 and SOT23-6 package.