16 Channel Servo Expansion Module

PWM Servo Driver 16-Channel 12-bit I2C (PCA9685)

The PWM Servo Driver 16-Channel 12-bit I2C (PCA9685) is designed for projects that require a large number of precise PWM outputs. Ideal for hexapod walkers, kinetic art, robotics, or LED control, this driver eliminates the limitations of microcontrollers with limited PWM pins. Using a simple I2C interface, it delivers reliable, free-running PWM control with minimal pin usage.

With the ability to control 16 PWM outputs using only two I2C pins—and the option to chain up to 62 boards on a single bus—this driver supports up to 992 PWM outputs in total.

Key Features

• 16 free-running PWM outputs with 12-bit resolution

• I2C interface requiring only two control pins

• Chainable design supporting up to 62 boards (992 outputs total)

• Adjustable PWM frequency up to approximately 1.6 kHz

• 12-bit resolution provides ~4 µs resolution at 60 Hz for servo control

• Built-in clock for continuous operation without tying up the microcontroller

• Configurable push-pull or open-drain output

• Output enable pin for quickly disabling all outputs

• 5V compliant for control from 3.3V microcontrollers

• Supports output voltages up to 6V

• Translucent body

• Lightweight design

• Less noise

Board & Electrical Features

• I2C 7-bit address range: 0x60–0x80, selectable via solder jumpers

• 6 address select pins for multi-board configurations

• Terminal block for external power input

• Optional 0.1" side breakouts for power input

• Reverse polarity protection on terminal block input

• Green power-good LED indicator

• 3-pin servo connectors arranged in groups of four (supports 16 servos)

• Dedicated capacitor footprint on the V+ line

• 220-ohm series resistors on all output lines for protection and LED driving

Dimensions & Weight

Power & Connectivity

• VCC pin powers the chip only

• V+ pin powers servos or LEDs and supports 3.3V–6V input

• External power supply via terminal block is recommended for servos

• Reverse polarity protection included

Arduino Connection (I2C)

Classic Arduino:

• 5V → VCC

• GND → GND

• A4 → SDA

• A5 → SCL

Arduino Mega (older pin layout):

• 5V → VCC

• GND → GND

• Digital 20 → SDA

• Digital 21 → SCL

Arduino R3 and later (Uno, Mega, Leonardo):

• 5V → VCC

• GND → GND

• SDA → SDA

• SCL → SCL

Servo Connection

Standard 3-wire servo connectors plug directly into the board:

• Ground: black or brown

• Signal: yellow or white

I2C Address Configuration

• Default I2C address: 0x40

• Address is set using solder jumpers on the board

• Each chained board must have a unique address

This PCA9685-based PWM driver provides a scalable, efficient solution for controlling large numbers of servos or LEDs with precision and stability.