LTC3543 drive white LED circuit diagram

Chip ceramic capacitor

Photocoupler

The LTC3543 operates in a 2.25MHz constant frequency, spread spectrum or PLL mode, providing a variety of options for low noise operation. Its current-mode configuration allows operation from an input voltage of 2.5 to 5.5V, making the device ideal for single-cell Li-Ion or multi-cell alkaline, NiCd, NiMH applications. The LTC3543 provides up to 600mA of continuous output current in a 2mm x 3mm DFN package. The LTC3543's switching frequency is as high as 2.25MHz, allowing the use of tiny, low-cost ceramic capacitors and inductors less than 1mm in height. LTC3543 drives white LED circuit: