Description:
Using only two pins, control 16 free-running PWM outputs! You can even chain up 62 breakouts to control up to 992 PWM outputs (which we would really like to see since it would be glorious).

• It's an i2c-controlled PWM driver with a built in clock. That means that, unlike the TLC5940 family, you do not need to continuously send it signal tying up your microcontroller, its completely free running!
• It is 5V compliant, which means you can control it from a 3.3V microcontroller and still safely drive up to 6V outputs (this is good for when you want to control white or blue LEDs with 3.4+ forward voltages)
• 6 address select pins so you can wire up to 62 of these on a single i2c bus, a total of 992 outputs - that's a lot of servos or LEDs
• Adjustable frequency PWM up to about 1.6 KHz
• 12-bit resolution for each output - for servos, that means about 4us resolution at 60Hz update rate
• Configurable push-pull or open-drain output
• Output enable pin to quickly disable all the outputs

We wrapped up this lovely chip into a breakout board with a couple nice extras

• Terminal block for power input (or you can use the 0.1" breakouts on the side)
• Reverse polarity protection on the terminal block input
• Green power-good LED
• 3 pin connectors in groups of 4 so you can plug in 16 servos at once (Servo plugs are slightly wider than 0.1" so you can only stack 4 next to each other on 0.1" header
• "Chain-able" design
• A spot to place a big capacitor on the V+ line (in case you need it)
• 220 ohm series resistors on all the output lines to protect them, and to make driving LEDs trivial
• Solder jumpers for the 6 address select pins

This product comes with a fully tested and assembled breakout as well as 4 pieces of 3x4 male straight header (for servo/LED plugs), a 2-pin terminal block (for power) and a piece of 6-pin 0.1" header (to plug into a breadboard). A little light soldering will be required to assemble and customize the board by attaching the desired headers but it is a 15 minute task that even a beginner can do.

Specifications:

• Dimensions (no headers or terminal block): 62.5mm x 25.4mm x 3mm
• Weight (no headers or terminal block): 5.5grams
• Weight (with 3x4 headers & terminal block): 9grams
• This board/chip uses I2C 7-bit address between 0x60-0x80, selectable with jumpers

Resources:

PCA9685 datasheet

Adafruit 16-Channel Servo Driver with Arduino

Adafruit 16 Channel Servo Driver with Raspberry Pi