The PCA9685 is an i2c bus controlled 16-channel LED controller red/green/blue/amber (RGBA) backlight application. Each LED output has its own separate PWM controller with a 12-bit resolution (4096 steps) with a fixed frequency programmable frequency from typical 24hz to 1526hz, and a duty cycle 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.
Block diagram
Each LED output can be turned off or on (without PWM control), or set in its separate PWM controller value. LED output drivers are programmed with 25ma current for open drain convergence capacity or totem pole at 5v, 25 Ma convergence, and 10ma source capacity at 5v. The PCA9685 operates in a voltage range of 2.3V to 5.5V with a 5.5V input and output tolerance. Leds can be directly connected to the led output (up to 25 mA, 5.5V) or controlled by an external driver with minimal discrete quantities for high current or high voltage LED components.
Pinning information
PCA9685 belongs to the new fast mode plus (Fm+) series. Fm+ devices cost more frequency (up to 1 MHz) and denser bus operation (up to 4000 pF). While the PCA9635 and PCA9685 have many similar features, the PCA9685 has some unique features that make it more suitable for backlit Ambilight applications such as LCD or LED
