The CAT3603 is a charge pump LED driver operating in either 1x (LDO) mode or 1.5x fractional mode regulating current through each of the 3 LED pins. Operation at a constant switching frequency of 1MHz allows the use of very small value ceramic capacitors. The CAT3603 drives 3 white LEDs in parallel and provides tightly matched regulated current to achieve uniform brightness in LCD backlighting applications. An external resistor, RSET, controls the output current level. The device can deliver up to 30mA over an input voltage supply range from 3V to 5.5V, making it ideal for battery-powered applications. LED dimming can be accomplished using several methods; using a DC voltage to set the RSET pin current, applying a PWM signal on the EN pin, or adding a switched resistor in parallel with RSET. The EN input pin allows the device to be placed in powerdown mode with 'near-zero' quiescent current. The device is available in the tiny 12-lead thin DFN 3mm x 3mm package with a max height of 0.8mm.