TPS75105,pdf(Low Dropout, Two-

The TPS7510x linear low dropout (LDO) matching LED current source is optimized for low power keypad and navigation pad LED backlighting applications. The device provides a constant current to up to four unmatched LEDs organized in two banks of two LEDs each in a common-cathode topology. Without an external resistor, the current source defaults to factory-programmable, preset current level with ±0.5% accuracy (typical). An optional external resistor can be used to set initial brightness to user-programmable values with higher accuracy. Brightness can be varied from off to full brightness by inputting a pulse width modulation (PWM) signal on each Enable pin. Each bank has independent enable and brightness control, but current matching is done to all four channels concurrently.