The PCA9685 is an I2C-bus controlled 16-channel LED controller optimized for LCD Red/Green/Blue/Amber （RGBA） color backlighting applications. Each LED output has its own 12-bit resolution （4096 steps） fixed frequency individual PWM controller that operates at a programmable frequency from a typical of 40 Hz to 1000 Hz with a duty cycle that is adjustable from 0 % to 100 % to allow the LED to be set to a specific brightness value. All outputs are set to the same PWM frequency. Each LED output can be off or on （no PWM control）， or set at its individual PWM controller value. The LED output driver is programmed to be either open-drain with a 25 mA current sink capability at 5 V or totem pole with a 25 mA sink， 10 mA source capability at 5 V. The PCA9685 operates with a supply voltage range of 2.3 V to 5.5 V and the inputs and outputs are 5.5 V tolerant. LEDs can be directly connected to the LED output （up to 25 mA， 5.5 V） or controlled with external drivers and a minimum amount of discrete components for larger current or higher voltage LEDs. The PCA9685 is in the new Fast-mode Plus （Fm+） family. Fm+ devices offer higher frequency （up to 1 MHz） and more densely populated bus operation （up to 4000 pF）。 Although the PCA9635 and PCA9685 have many similar features， the PCA9685 has some unique features that make it more suitable for applications such as LCD backlighting and Ambilight：