ADP5520 is a backlight driver with I/O expansion from Analog Devices. It adopts an efficient asynchronous boost converter to drive up to 6 white LEDs. The input voltage range is 2.7 V to 5.5 V, and it can be programmed with 128 levels of backlight LED current (up to 30 mA). It also features ambient light sensing with autonomous backlight adjustment, programmable backlight fade-in/fade-out times, programmable backlight dim and off times. In addition, it has 8 configurable GPIO pins (input, output, up to 4x4 keypad), up to 3 auxiliary LED current sinks (1 dedicated, 2 configurable), 64 programmable auxiliary LED current levels (up to 14 mA), programmable auxiliary LED fade-in/fade-out times, programmable auxiliary LED on and off times (allows blinking), I2C-compatible serial interface, interrupt line for signaling an external processor (nINT), and hard reset (nRST). It also has current limit protection and thermal overload protection. The product is available in a small package and can be widely used in portable devices, laptops, desktops, TVs, and other electronic devices.